That sounds scary, right? What is happening?. Here are the facts.
The “Mystery object” was discovered on 1 July 2025 by ATLAS (Asteroid Terrestrial-impact Last Alert System). ATLAS is a cooperation of earth-based observatories that continuously watch the sky, looking for moving astronomical objects. ATLAS started in 2015 and currently five observatories are taking part. They specialise in looking for smaller asteroids that may impact Earth and can only be detected when they are close. a last alert. Until now they have found 1241 Near-Earth asteroids, of which 110 were potentially hazardous. But also other objects were found, 106 comets and 4847 supernovae (which don’t move but change brightness)
The object found on 1 July is a comet, but it is causing huge excitement in the scientific community because of its extremely high speed. That means it comes from outside our solar system, will be slightly deflected by the Sun, and will escape again. Here is its (hyperbolic) orbit. The (animated) image comes from Wikipedia: 3I/ATLAS
The Wikipedia article contains a massive amount of information about 3I/ATLAS, a proof of the excitement caused by its discovery. Two more pictures from Wikipedia, the original discovery photo (animated gif) and a detailed photo taken by the Hubble telescope on 21 July.
The fuzziness of 3I/ATLAS in the Hubble picture is characteristic of a comet. The icy nucleus is hidden in a coma, water and dust evaporated by the solar radiation. That’s why the present estimate of its size is very inaccurate ( between 0.32 and 5.6 km). The comet will reach its perihelion (closest distance to the Sun) on 29 October and will never come closer to Earth than 209 million km (on 19 December).
Until now, three interstellar visitors have been detected: 1I/’/Oumuamua in 2017, the interstellar comet 2I/Borisov in 2019, and now 3I/ATLAS. In my blog post of February 2018, Oumuamua, I discussed in detail the first interstellar visitor. Now we have another one.
So, why the consternation in the popular press and the social media, like here or here or here. Google for 3I/ATLAS alien and you will find more links.
In my Oumuamua post, I wrote: “Of course, there are people who are wondering if it could be a spaceship”. Basically, it was one man who suggested this, Avi Loeb, an astrophysicist at Harvard University. He was widely criticised by the scientific community. He even wrote a popular science book about it: Extraterrestrial. The consensus is now that Oumuamua is just a physical object.
As largely a pedagogical exercise, in this paper we present additional analysis into the astrodynamics of 3I/ATLAS, and hypothesize that this object could be technological, and possibly hostile as would be expected from the ‘Dark Forest’ resolution to the ‘Fermi Paradox’
He also has a blog and wrote two posts about 3I/ATLAS, on 17 July and 5 August . And two weeks ago, he was interviewed by FOX 10 Talks. Click on the screenshot to watch the video. The interviewers are in awe that, for the first time, they have a Harvard professor in their program.
When Loeb is right about 3I/ATLAS, that it might be an alien, hostile spacecraft, what about November? Here is a possible scenario.
The spacecraft, disguised as a comet (!), reaches perihelium on 29 October. If you look at the animated GIF above, you will see that Earth is then on the other side of the Sun, so 3i/ATLAS will not be visible to us. During that period, the spacecraft will change its course and when it is visible again, it will come to attack and destroy us!
Just when I was ready to publish this post, I came across this website: Elon Musk: “It’s Confirmed, The 3I ATLAS is an Alien Space Craft!”. I am sure the mention of Musk is fake, only meant to attract more viewers. But the YouTube video on the website is fascinating, a mixture of science and sc-ifi. Click on the screenshot to watch the video.
Don’t worry. It’s a comet, not a disguised alien spacecraft.
Here is a promise. If humanity is still alive after November, I will write a post about the Fermi Paradox and the Dark Forest. And about my solution, the Rare Earth hypothesis.
In April 2016 I published a post Our Solar System, an update. At the end of this post I wrote about the New Horizons mission, that it was on its way to the Kuiper Belt, after a successful flyby of {luto.
Here is the Kuiper Belt, a ring of (mainly) small icy bodies orbiting the sun beyond the orbit of Neptune. The distance scales are in Astronomical Units (AU), where 1 AU is 150 million km. the average distance between Earth and the Sun. The locations of Jupiter, Saturn, Uranus, and Neptune are given. Earth and the other planets are inside the yellow blob in the center. The grey cloud between this blob and Jupiter represents the asteroid belt.
More than 3000 Kuiper Belt Objects (KBOs) have been found and that number is increasing yearly. Many of them are (relatively) small, like, for instance, the 2014 MU69, mentioned in my 2016 post as the next destination for New Horizons. Another flyby on 1 January 2019 was very successful. Here is an image of 2014 MU69, taken by New Horizons. It is a contact binary, dimensions ~40x20x10 km, now renamed Arrokoth. See the appendix about naming (and renaming) objects in the Solar System.
The official name for any object orbiting the Sun beyond Neptune is Trans-Neptunian Object (TNO). Some of them can be quite large. In 2005 Eris was discovered, with a diameter of ~2300 km, about 1/5th of Earth’s diameter, similar in size to Pluto. A heated discussion among astronomers led in 2006 to the demotion of Pluto as a planet and the introduction of a new concept: dwarf planet. Pluto was always an odd one out with its elliptical orbit. It is now a dwarf planet, like Eris. Here is the Outer Solar System.
More dwarf planets have been discovered in the region beyond Neptune. A fascinating one is Sedna, discovered in 2003. Its orbit is extremely elliptical, its distance to the Sun varying between 76 and 937 AU, far outside the Kuiper Belt. One orbit takes 11.400 years, Various estimates for its diameter, Wikipedia gives >1000 km. Here is the orbit of Sedna in orange. The Outer Solar System is now so tiny, the Kuiper belt is marked in blue.
Also shown is the orbit of 2012VP113, in red. Discovered in 2012, diameter ~600 km. Again very elliptical, distance to the Sun between 80 and 460 AU. One orbit takes ~4500 years. You may wonder how astronomers discover such a remote object and even determine some of its properties. In the picture you can see how. Three images, taken by a powerful telescope, with a 30-minute interval, have been superimposed. Look at the small dot in the center. That is 2012VP113, moving against the background of stars
One more extreme TNO, 2015TG387, was discovered in 2015. Its aphelion (the farthest distance from the SUn) is a staggering 2114 AU. The orbital period is about 40.000 years.
More of these extremely elliptical TNOs have been found. What can have been the cause? . Not the giant planets or the Kuiper Belt, they never come close enough to feel their gravitation.
In 2016, two astronomers, Batygin and Brown, came up with an interesting hypothesis. A planet with a mass of about ten times that of Earth, orbiting the Sun in an elliptical orbit between 280 and 1120 AU, orbital period of 5000 years, could explain the orbits. In the diagram, the orbit of this hypothetical Planet Nine is shown.
P[anet Nine has not yet been found and it will not be easy. Not all astronomers are convinced that it exists, but it generated a lot of interest in extreme TNOs.
Recently, a new one has been found 2017 OF201. First observed in 2017. Distance to Sun between 45 and 1630 AU. Orbital period 24.000 years. Here are again three superimposed pictures, this time taken with an interval of 1 hour. Estimated diameter ≈ 550 to 850 km.
In an appendix I will tell more about the interesting way this extreme TNO was discovered and how an estimate could be made about its size. The evidence presented was so convincing that on 21 May TNO 2017 OF201 was accepted by the authoritative International Astronomical Union (IAU) as a new dwarf planet. I flurry of articles in magazines and newspapers followed. Some are accurate, like the EarthSky one, others contain errors, like the Yahoo!News one.
Here the orbit of 2017PF201 is added in red to the other TNOs. The supposed orbit of PLanet 9, here called Planer X, is shown in black.
As you see, the orientation of this new TNO is completely different from the others! And that is a serious challenge for the Planet 9 theory. Model calculations show that Planet 9 would strongly disturb the orbit of 2017 OF201 and, in the future, would kick it out of the solar system. So, does Planet 9 really exist?
That was the ending I had in mind for this post.
But, very recently another interesting article was published, claiming that PLanet 9 may have been found! Click here for the original publication (quite technical). The idea is “simple”. Planet 9 will be cold, but still it emits (thermal) infrared radiation. The authors use data from two infrared missions, IRAS (1983) and Akari (2006), comparing them, filtering out all known infrared sources and looking for an area, that doesn’t move within a few months, the operating time of both missions, but is found in a different location after 23 years. They find one suitable candidate, which fits with the theoretical orbit of Planet 9. Amazing.
I am sure that this is not the end of the story 🙂 .
____________________________________________
Appendix 1 Naming/renaming of astronomical objects in the solar system
All astronomical solar system objects (except comets), smaller than planets, are called minor planets (planetoids). Asteroids, KBOs, TNOs, and dwarf planets. The Minor Planet Center keeps track of them. When a new minor planet has been discovered, it gets a name. For the new dwarf planet, this (provisional) name is 2017 OF201. Here is the explanation. 2017 was the year it was first observed. Followed by two letters.
The first letter, O, tells in which half-month of that year it was discovered, in the second half pf JUly 2017. The second letter gives the order of discovery for that half-month. The F would naan that it was the sixth minor planet discovered in that half-month. But wait. When this coding was designed ( in 1925), it could handle 25 discoveries in a half-month, but nowadays, with modern technology, there are many more. That’s why the subscript is added. 201 x 25 = 5025 +8 = 5033. This dwarf planet was the 5033th discovery in the second half of July 2017!
When the orbit is determined accurately enough, this provisional designation is replaced by a (sequential) number. The team that discovered the minor planet can then suggest a name. The minor planet 2014 MU69, visited by New Horizons, is now named 486958 Arrokoth. Using the coding given above, you should be able to check that Arrokoth was the 745th discovery in the second half of June 2014.
___________________________________________
Appendix 2 T The discovery of dwarf planet 2017 OF201.
The original article can be found here. The authors use data from the Dark Energy Survey project, which itself is not related to the solar system. To find objects in the solar system, you must look for objects that move. Using the survey data, already ~800 TNOs have been found. The next step is to find the distance of the object. For that we use the apparent motion of the object against the background of the stars. It is called parallax. Due to Earth’s orbit around the Sun, the position of the object changes. From how much it changes, the distance can be calculated. For 2017 OF201 this distance is at the moment about 90 AU.
The combined effect of parallax and real motion for 2017 OF201 is shown in this diagram
The oval (due to parallax) is moving throughout the years. Observation dates are indicated.
From the amount of light, combined with the distance, a rough estimate can be made of the size. For 2017 OF201 this results in a diameter of 550 to 850 km . Big enough to call the object a dwarf planet.
Before you start protesting, we are not talking about the Western (Gregorian) calendar but about the Chinese one 😉 .
In the Western calendar, a year has 365 days, but one orbit of Earth around the Sun takes 365.25 days, 6 hours more! To compensate for this shortage, an extra day is added (29 February), when the year is divisible by 4. As 2025 is not divisible by 4, it is NOT a leap year. Have a look at Appendix* f for more details.
MoonThe Chinese calendar is a lunar calendar, based on the orbit of the Moon around the Earth. One orbit takes on average 29.53 days. Therefore, a lunar year is 12 x 29.53 = 354.36 days, 11-12 days shorter than the solar year.
As a result the lunar year moves forward 11-12 days yearly with respect to the solar year. The Islamic calendar is doing that.
Does that matter? It depends, for an agricultural society it does, because a lunar calendar has no relation with the seasons.
The solar year has seasons because the Earth’s axis is tilted. Here is a diagram. There are two times when the Sun is right above the equator. Day and night are of equal length all over the world. They are called the Spring equinox (~ 21 March) and the Autumnal equinox (~21 September). Around 21 June, the Sun reaches its northernmost position, the Summer Solstice, when daylight is at its maximum in the Northern hemisphere. Half a year later, the daylight is minimal. around 21 December, the Winter Solstice. (Of course in the Southern hemisphere it is just the other way around).
I wrote “around” and in the diagram a few dates are mentioned. In Appendix 2 I will explain why the dates vary, although the events are fixed.
Another way to describe the location of the Sun, is by using degrees (ecliptic longitude is the technical term).. We start at the Spring equinox (0°), and go counterclockwise. Then the Summer solstice is at 90°, the Autumnal equinox at 180°, and the Winter solstice at 270°.
Can we also divide the solar year in months? Sure, by dividing the Sun’s orbit in 12 sectors, each of 30 degrees. Each sector corresponds to a solar month. It is what the Chinese solar calendar does. It introduces 24 Solar Terms, two for each month, one for the start and one for the center. It is called the Center Point of that month. (similar to a Full Moon day in the lunar calendar). Here is a diagram of the 24 Solar Terms.
The diagram contains lots of information, the names of the solar terms (in English and Chinese) and the approximate dates. When you are Chinese, you may find a few familiar names: Qing Ming (15°), Dhong Zhi (270°) and Li Chun (315°). More about this in Appendix 3.
To explain the lunisolar calendar, we need the dates for the lunar and the solar months. Lunar data( for the years 2005-2045) can be found here and the Solar Terms (for the years 1900-2049) are here.
Here is the info for the first lunar month in 2025. The link above gives 29 January at 20:35 for the New Moon. So, the first month of CNY starts at 29 Januarty. The next New Moon is at 28 February, so the last day of the first month is 27 February.
The Solar calendar starts with Li Chun (the beginning of Spring). Using the Solar Terms link above, we find the date for that solar term: 3 February at 22:10, so the first solar month starts on 3 February. The next solar term (Rain Water) is at 18 February 18:-0, so tne Center Point is on 18 February. I have collected the results in the table below. The first lunar month contains the first solar center point.
I have done the same for the next two lunar months.More or less the same but the Solar Center Point shifts to more the end of the lunar month (8 resp. 7 days). That makes sense because a solar month is slightly longer than a lunar month.
Here are the other months for 2025. Notice the month I have given a blue color.
As you see there is a lunar month that doesn’t contain a solar center point!. When that happens, that month is considered a leap month. It just duplicates the earlier month. The result is that a lunisolar leap year contains 13 lunar months.
Notice how after the leap month the solar center point is at the beginning of the lunar month. Each lunar month it will advance 1-2 days, so after 2-3 years there will be another leap month. Not necessarily the sixth month, like this year. See Appendix 4.
In the Chinese lunisolar calendar, a lunar month is a leap month when it does NOT contain a solar center point.
Appendix 1 About a leap year in the Gregorian Calendar
A leap day is added when the year is divisible by 4. This makes the length of a year 365 + 1/4 = 365.25 days. But the solar year is actually 365.2422 days, slightly less. Therefore, the Gregorian calendar has a second rule: when the year is divisible by 100, it is NOT a leap year; This makes the average year length 365 +1/4 -1/100 = 365.244 days. A better approximation, but it can be made even better by a third rule: when the year is divisible by 400, it IS a leap year; making the average year length 365 + 1⁄4 − 1⁄100 + 1⁄400 = 365.2425 days. More information about leap years can be found here.
Appendix 2: Why do the dates for solar terms vary, while the events are fixed.
Because a normal year is 6 hours short of a solar year, the solar terms will shift 6 hours! Take for example Li Chun. In 2025 it falls on 3 Fberuary at 22:10, but in 2026 on 4 February at 4:02. Six hours later, so next year Li Chun will fall on 4 February. Another cause of variability is the time zone system we are using on Earth. All dates and times in this post are in China/Malaysia time (UTC + 8). in that timezone the Summer Solstice falls in 2025 on 21 June at 2:42. New York is using Eastern Time (UTC-4), the Summer Solstice in that timezone is 12 hours earlier and falls on 20 June 22:42, one day earlier.
Appendix 3 About Dong Zi, Qing Ming and Li Chun
The Chinese festivalls follow the Lunar calendar , with three exceptions. Around Qing Ming (Cheng Beng) Chinese families visite the graves of their ancestors. `And around Dong Zhi, Chinese celebrate the harmony in the family. Li Chun is of special imporatnce for the believers in Feng shui. All three belong to the solar calendar, they don’t move around.
Appendix 4: How to find a leap month
You don’t need mathematics to find a leap month, just the tables for moon phases and solar terms as given above. Solar Center Points advance relative to lunar months, so we must find a lunar month where the Solar Center point falls on the first day of that month. We have to continue until 2028 before we find a month that fits that condition. Here is the relevant part of the table for 2028
I2028 will be a leap year, the 5th month will be duplicated.
In the 1991 edition of the Guinness Book of Records the Mandelbrot Fractal is mentioned as Most complex object in mathematics? , with as explanation: A mathematical description of the shape’s outline would require an infinity of information and yet the pattern can be generated from a few lines of computer code.
Here is the Mandelbrot Fractal.
When you zoom in on the outline of the fractal, you will see more and more details.
And you will notice that there are smaller copies of the Mandelbrot.
Connected to the main shape in a complicated way.
Same shape, but often a bit distorted.
Infinite detail.
I learned about the Mandelbrot fractal around 1985 and got hooked right away ;-). On my PC I wrote programs to generate the Mandelbrot Fractal myself. In 1988 I attended a symposium organised by the Delft University, Fractals and Computed Art. I submitted one of my fractal images to a contest but didn’t win a prize :-(. I gave talks about the topic to my students and in 1990 to a group of senior citizens..
More than ten years later I built my own website and of course part of it was about fractals.One page, Fractals, describes in more detail than above my experiences with the Mandelbrot fractal. The page has many broken links. but is still worth reading . I also wrote a tutorial, (in Dutch). aimed at high school students, It became quite popular, because I had written a number of interactive Java applets, where you could play around with the various aspects of the Mandelbrot Fractal.
However, in the years that followed, it became more and more difficult (and now even impossible) to run Java applets, because of the security risks involved.
A few months ago, after talking with friends, I decided to translate the tutorial into English and look for a replacement of my applets. There are many interactive applications on the internet related to the Mandelbrot Fractal, but it took me time to find the ones that fit well with my tutorial.
I am very pleased with the final result. Click on the screenshot below to enter the tutorial.
Here is a Google Earth image showing part of Sumatra with its capital Medan. The Malaysian coast is at the right with the harbour of Port Klang. Lake Toba, about 100 kilometres long, 30 kilometres wide, and up to 505 metres deep is the largest volcanic lake in the world. Volcanic? Yes, about 74.000 year ago, there was a volcanic eruption, the largest-known explosive eruption on Earth in the last million years. The eruption left a caldera, which is now lake Toba.
There exists a classification for explosive volcanic eruptions, similar to the Richter scale for earthquakes. It is called the Volcanic Explosivity Index (VEI). During an explosive volcanic eruption lots of (molten) rocks and ash (called tephra) are expelled into the air and it is the (estimated) volume of this tephra that is used to classify the eruption. Here is the VEI scale. Like the Richter scale it is logarithmic, each following step means a ten-fold increase in ejected volume. The “How often?” row gives an estimate of the frequency of the eruption, not surprisingly huge eruptions are very rare. There is an older classification of volcanic eruptions, Strombolian, Plinian etc, see Eruption Classifications. The last row gives an estimate of the plume height.
Here are a few examples
The Etna is Europe’s largest active volcano located in Sicily in southern Italy. On average it has a VEI index of 2. I visited this volcano twice, in July 1971 and July 1979. In 1971 it had erupted in April. Lava flows had caused a lot of damage and it was a special sensation to walk over solidified lava that was still hot under your feet. In 1979 it erupted in August but during my visit I still could climb up to the rim of the crater.
The Vesuvius volcano is also located in Italy, near Naples. It is not very active at the moment but erupted in 79 AD. spewing 3.25 km³ of tephra, destroying the cities of Pompeii and Herculaneum. VEI index 5. A catastrophic event.
And that is only VEI-5. Here is the island Santorini in Greece, Or rather what is left of it after a volcano erupted on the island circa 1600 BCE . The eruption volume is an estimated 34.5 km³, so the VEI index is 6. In the center of the caldera two small volcanic islands have been formed. There is still a lot of discussion about the exact date of the eruption, it may have caused the downfall of the Minoan culture.
VEI-6 eruptions are not rare, they occur globally with a frequency of 50-100 years. In 1883 the Krakatoa erupted (8–25 km³ ) . Similar to Santorini, in the resulting caldera a volcanic island, Anak Krakatoa has formed. In this photo seen in the foreground, with Krakatoa in the background.
The most recent VEI-6 eruption was Mount Pinatubo in 1991 with an erupted volume of 12.5 km³ Two photos, one taken about one month after the eruption, the other one taken in 2012, where a lake has formed in the caldera. What a contrast 😉
In recorded history there is only one VEI-7 eruption, Mount Tambora in 1815 with an eruption volume of 144–213 km³ Located on the Indonesian island of Sumbawa, it is now a tourist attraction. The caldera is 6-7 km wide and 600-700 meter deep.
VEI-7 eruptions are so powerful that the plume reaches the stratosphere. This can lead to a volcanic winter event. The lighter particles and ash fall/rain down, but the plume also contains massive amounts of gases like SO2 and H2S which in the stratosphere react with OH and H2O to form H2SO4 (sulphuric acid) aerosols. They reflect the sunlight, remain in the stratosphere for months or even years and spread globally. The effect is a temporary climate change, affecting crops etc. The year 1816, one year after the Tambora eruption was a Year Without a Summer ! Average global temperature was 0.4–0.7 °C lower, causing major food shortages in many countries.
After this long introduction, it’s time to come back to the Toba eruption. Because it happened so long ago, the estimates of the ejected tephra are of course less accurate, they vary between 2000-13200 km³ A recent one gives 8600 km³. Meaning that the Toba eruption was at least a VEI-8 (more than 1000 km³) and possibly even a VEI-9 (more than 10.000 km³).
How much is 8600 km³? Well, if all that tephra would be deposited over Peninsular Malaysia, it would result in a layer of about 65 meter thick!
When you compare the Tambora eruption with the Toba eruption, Toba should have resulted in a much stronger volcanic winter, possibly lasting many years if not decades.
Could such a volcanic winter have affected our species, Homo Sapiens ? The Toba eruption happened during the Last Glacial Period . It was in that same period that waves of Homo Sapiens migrated out of Africa. This graph shows global temperatures during the last 150.000 years. The Eemian and the Holocene (our present era) are warmer Interglacials. During the Last Glacial Period temperature dropped as did the sea levels. See my blog posts Ice Ages and Sundaland. As you see in the graph, the temperature variations are rather irregular. There are markers for the Out of Africa waves and the Toba eruption
In this map the spreading of Homo Sapiens is shown (in red) together with the distribution of earlier human ancestors, the Neanderthals and the Homo Erectus. In 2012 I did a DNA-test to find out when my ancestors left Africa. For my paternal ancestor that was around 50.000 years ago, my maternal ancestor left earlier, ~70.000 years ago. Both after the Toba eruption. Here is my blog: My ancestors .
The Homo Sapiens population in Africa was small and the migrating groups even smaller, think about numbers in the thousands. They were hunter-gatherers. Sudden climate change might threaten their existence. The Toba Catastrophe Theory, developed a few decades ago, holds that the Toba eruption caused a global volcanic winter, leading to a near extinction of Homo Sapiens, causing what is called a (human) genetic bottleneck. Here is an illustration of a genetic bottleneck. Because only a small number of individuals survives the bottleneck, their genetic diversity is limited.
It is generally accepted that there have been many bottlenecks in the human evolution, Click here for an article about it. And a few months ago Scientific American published an article Human Ancestors Nearly Went Extinct 900,000 Years Ago That was the time of Homo Erectus, long before Homo Sapiens evolved.
The Toba Catastrophe is controversial. Did the Toba eruption produce a bottleneck? Was the Toba Volcanic winter so severe and long lasting that the global population of Homo Sapiens was reduced to about 1000 breeding pairs?
One vocal proponent of the Toba Catastrophe is Donald Prothero, an American geologist , paleontologist and prolific writer In 2018 he published When Humans Nearly Vanished about the Toba Catastrophe.
But here is an equally vocal opponent, John Hawks, an American paleoanthropologist with a popular blog, who wrote in the same year 2018: The so-called Toba bottleneck simply didn’t happen. He mentions research that humans thrived in South Africa during the Toba eruption.
I am not an expert, so don’t expect a verdict from me 😉
Nowadays Lake Toba and Samosir are tourist attractions of Sumatra. Here is a more detailed Google Earth image. Samosir was originally a peninsula until in 1907 a canal was opened through the isthmus.
I have visited Samosir in 1994, thirty years ago, I don’t remember much about it. Peaceful, interesting Batak culture. You don’t realise that you are staying on top of a dormant volcano. Deep below Lake Toba is a huge magma chamber (50.000 km³ ) that is filling up slowly with magma. This has lifted Samosir already around 450 m. Will there be another supervolcano eruption? Yes, but no need to worry, that may take another 600.000 years.
One year ago I wrote a post about the Paleomap Project. At the end of that post I included a link to the Story of the Malay Peninsula. Here it is again. The clip is less than 3 minutes and worth watching.
I ended my post with: Notice how during the Ice Ages the sea-level was so low that the islands of the Malay archipelago were connected. This was called Sundaland. Topic for another post.
Here is my post about Sundaland.
What is actually an Ice Age?
Probably most people will first think about the funny Ice Age movies, but hopefully many will also know that there has actually been a period in Earth’s history, where the climate was cold and a large part of the Earth (North America, Europe) was covered with ice. That was about 21 thousand years ago and it is commonly called the Ice Age. Here is a Paleomap of Earth during that time.
Notice that the map doesn’t say Ice Age, but Last Glacial Maximum ! I got interested, Googled a lot and wrote a separate post Ice Ages. Here is a summary.
In the 4.5 billion years of its existence, Earth has been mostly (~85%) a Greenhouse, no icecaps, icesheets, glaciers. But there have also been at least five major periods that Earth was an Icehouse, partially covered with ice. These Icehouse periods are called Ice Ages. At this time Earth is in the Late Cenozoic Ice Age, which started 34 million years ago.
In an Ice Age there is always permanent ice, but the amount fluctuates. There are periods that the ice advances, they are called glacials. And there are periods that the ice retracts, called interglacials.
The last glacial was about 21.000 years ago and is often called the (Last) Ice Age. At the moment we are living in an interglacial, icecaps, icesheets, glaciers are retracting. But Earth is still an Icehouse.
There have been numerous glacials and interglacials in those 34 million years. Here the global temperatures for the latest are shown. Notice that the timescale is from right to left, so the last glacial (“the Ice Age”) is the rightmost snowflake. And there is an obvious regularity with a period of roughly 100.000 year. If you want to know more about the theory, read the Milankovitch Cycles article in Wikipedia.
In this blog we are especially interested in sea levels. During a glacial a lot of water is frozen in icecaps, icesheets and glaciers, so the sea level drops, and during an interglacial ice melts and the sea level rises. Here are the sea levels during the last 400.000 years. In the original graph time goes from left to right, I have flipped it to make comparison with the temperature graph easier. Notice the similarity between temperature and sea level. During interglacials sea levels were about the same as nowadays, but during glacials they were up to 120 meter lower.
I will now concentrate on the last 150 thousand years, Here is a more detailed temperature graph. Starting from the left, we see the end of the Penultimate Glacial at about 135 thousand year ago. It was a very cold one. Then, relatively quite fast, temperatures are rising, until they reach a maximum at 125 thousands year ago in the Eemian Interglacial. Warmer than nowadays, sea level 6-9 meter higher (!) than today. After this maximum, slowly and irregularly , temperatures are dropping, until a new glacial maximum is reached, about 21 thousand years ago. After this the temperature rises again and we reach the Holocene interglacial in which we are living nowadays.
This time period is very interesting for homo sapiens. Indicated are two waves of migration out of Africa. And about 74.000 year ago the Toba volcano on Sumatra erupted, one of the largest eruptions in Earth’s history. Present day Lake Toba is occupying the caldera of this eruption. There is a theory that this eruption almost caused the extinction of homo sapiens, but this Toba catastrophe theory is something for a separate blog.
We zoom in one more time and look at the sea level. It was 120 m below present during the last glacial maximum, then rising more or less gradually until it reached present levels around 6000 years ago. Around 12-14 thousand years ago, there was an interruption with a cold period (Younger Dryas). Also notice the steep increase around 14 thousand years ago, caused my melting icesheets , about 5 cm per year !
A sea level rise of 120 meter is enormous. Here is a Google Earth screenshot of South East Asia. The color of the sea indicates how deep it is, light blue is shallow, dark blue deep. When you open Google Earth on your computer and move your cursor over the screen, the depth is indicated. I have done that for three locations, and found 50, 30 and 40 meter.
When the sea level drops 120 m, the whole light blue region would become land!
Here is how the region would look like, 21 thousand year ago. Sundaland! A continental shelf, exposed when the sea level is low. If there had been public transport in those days, you could have traveled overland between Indonesia, Malaysia, Thailand, Cambodia en Vietnam! And in the far future, during the next glacial, that will be possible again 😉 .
Here is a video, where you can follow Sundaland from the last Ice Age until present. Only 44 seconds, worth watching. Created by Dhani Irwanto, more about him later.
There are more regions on Earth where something similar has happened. In the lower right part of the video, you can see part of the Sahul shelf. During the last Ice Age Australia and New Guinea were connected.
And in Europe during the last Ice Age, England, Ireland and mainland Europe were connected. The continental shelf is called Doggerland. Around 6500 year ago England became an island (again).
One more example. During the last Ice Age Tamil Nadu and Sri Lanka were connected. In this Google Earth image I have roughly marked the contour line (isobath) of 120 m below sea level. Some land is now submerged but not a continent as some Tamil nationalists still believe. See my blog Kumari Kandam & Lemuria.
Sundaland is a huge landmass (~ 1.8 million km2), now partially submerged. but large during the time that homo sapiens migrated out of Africa. Here are some of these Early Human Migration routes.
1in 2012 Aric and I took part in the Genographic Project , we sent samples of our DNA and got it analysed. It resulted in this map with the routes followed by our (maternal) ancestors. Read my blog My Ancestors for more details.
As you see there are migration routes to South East Asia and Sundaland. Could it be that during this last glacial there was a civilisation in Sundaland, later destroyed by the rising sea levels? Could that have been the lost continent, Plato’s Atlantis? Or the Garden of Eden?
In the last few decades, three books have been published advocating exactly that. In 1999 Stephen Oppenheimer published Eden in the East. According to him it was Sundaland where the first human civilisation started. After Sundaland became flooded (Noah’s flood!), the population dispersed and fertilized the cultures of Mesopotamia, Egypt, China and India. A few years later, in 2005, Arysio Santos published Atlantis, the lost continent finally found. Santos was convinced that Sundaland was the Garden of Eden and Plato’s Atlantis. Quite recently, in 2019, Dhani Irwanto published Sundaland: Tracing The Cradle of Civilizations. Same approach. All these books are still for sale at Amazon.
It’s a fascinating topic, and there is no doubt that Sundaland existed. But Atlantis, the Garden of Eden, the Cradle of Civilisation? Here is some information about the authors.
Stephen Oppenheimer (1947-) is a British paediatrician and geneticist. After 1997 he started a new career as a researcher and popular-science writer on human prehistory.
Arysio Santos (1937-2005) was a Brazilian nuclear engineer, but “his true hobby in life was researching arcane subjects such as Symbolism, Alchemy, the Holy Grail, Comparative Mythology and Religion” (quote from his own website)
Dhani Irwanto (1962 -) is an Indonesian hydro civil engineer. Founder of Indonesia Hydro Consult in 2010 and its director until now. Became interested in Sundaland and has written books about it.
The authors have in common they have no formal training in the subject matter. They were captivated by the subject and delved into all aspects of it, climatology, geology, linguistics, anthropology etc. Their approach, especially Irwanto’s, tries to be scientific. But it is still Fringe Science, outside the mainstream discipline.
I was considering to buy Irwanto’s book, but then I discovered a video Tracing the Cradle of Civilisations in Sundaland, about a lecture he gave in the Philippines in 2017 at an Asean Advanced Archaeology Symposium. Brilliant presentation, worth watching (28 minutes).
But he is really going too far in his enthusiasm. Here is a screenshot from the video. Everything, all over the world , originated in Sundaland. So I may not buy the book.
What is an Ice Age? And how many Ice Ages have there been on Earth? I came across these questions, while writing a blog post about Sundaland. During the Ice Ages the sea level was much (~ 120 meter) lower than at present and the islands of the Malay archipelago were connected to Thailand, Cambodia and Vietnam. This landmass was called Sundaland. In my blog Sundaland (still under construction) I write in more detail about it.
If what follows is too detailed for you, just jump to the summary
During the 4.5 billion years that Earth existed, Its climate has fluctuated between Greenhouse and Icehouse. During a Greenhouse there were no glaciers, no icecaps (South Pole), no Ice sheets (Greenland) no permanent sea ice (North Pole). Earth was mostly a greenhouse , about 85 % of the time. Temperature was (a lot) higher than at present. Sea levels higher, sometimes 300-400 meter. Lots of carbon dioxide in the atmosphere. Tropical rain forests on the South Pole 😉
But there also have been Icehouses, often called Ice Ages, where glaciers, icecaps and ice sheets were permanently present. Scientists have identified 5 of them. Here they are marked on the 4.5 billion year timescale that Earth existed.
The Hadean, Archean and Proterozoic are the first three “aeons” of Earth’s geological history. We are now living in the last aeon , the Phanerozoic, which started ~ 542 million years ago, the name is too long to be named in the image. Before I “zoom in” on this last aeon, a few comments, related to blogs I wrote in the past.
Only a few million years after the formation of Earth, in the Hadean, our Moon was “born” as a result of a collision of Earth with another planet. Where does the Moon come from? .
The oldest fossils date back to the Archaean, 3.4 billion years ago, when Earth was still young. Therefore many think that life comes easily and must be ubiquitous in the universe. I am sceptical, see my blog The Drake Equation.
It took a long time before those simple cells evolved and developed a nucleus that contained the DNA, about 2,2 billion year ago in the Proterozoic. And it took even longer for multicellular organisms to develop, about 600 million year ago, at the end of the Proterozoic. See my blog The Tree of Life.
The Proterozoic had two Ice Ages. The Huronian actually consists of several separate Ice Ages and lasted about 300 million years The Cryogenian also has two separate Ice Ages, together lasting about 85 million years. The Cryogenian was severe, there may have been periods that Earth was completely covered with ice, a so-called Snowball Earth.
.Keep in mind that Earth looked very different in those days because of plate tectonics and continental drift. See my blog The Paleomap Project. Here is one of Scotese’s maps: Earth during the Cryogenian Ice Age.
Now let’s zoom in on the Phanerozoic, from 542 million year ago until present. The ‘official’ start of this aeon is 538.8 million year ago. This beginning was chosen because around that time a sudden , explosive diversication of life forms started, the Cambrian explosion. Multicellular organisms evolved into a multitude of species. Here is an artist impression.
The Phanerozoic had three major Ice Ages, the Andean-Saharan, 440 million years ago, lasting 40 million years, the Karoo , 300 million years ago, lasting 100 million years and the current one, the Late Cenozoic Ice Age , which started 34 million years ago and is still ongoing.
Here is a (complicated) graph of the global temperature during the Phanerozoic. Complicated because the timeline has been split in five parts, zooming in.
The first part (in red) covers from 542 Million years (Ma) until 66 Ma. The temperature data are less reliable, but you can see the Andean-Saharan (440), the Karoo (300) and an unnamed one (~180). Next comes the green part, timeline enlarged about 10 times, from 66 Ma until ~ 5 Ma. Around 66 million years ago a huge asteroid collided with Earth, causing the extinction of the dinosaurs and giving mammals the opportunity to develop. Earth was a hothouse then with a maximum temperature around 55 million years ago (PETM). After that maximum, global temperature started to decrease. Around 34 million years ago, Antarctica got an icecap and Earth became officially an Icehouse, the Antarctic Glaciation . The next zoom in (again x10, in black) shows how the cooling of Earth continued. Around circa 2.58 million years ago the Pleistocene started, ice “everywhere”, also in the Arctic region.
The next part, in blue, shows in more detail the last one million years of Earth. It’s clearly an Icehouse but there are periods which are colder (glacials) alternating with warmer ones (interglacials). If you would be able to watch Earth during this one million years, you would see the icecaps and ice sheets advancing during glacials and retreating during interglacials. The last of these “warmer” interglacials was the Eemian (130-115 thousand year ago. Followed by the last glacial (26-20 thousand years ago). It is this last glacial that is often, called the Ice Age.
At present Earth is in an interglacial, as can be seen in the last part of the graph (also in blue). This interglacial started around 12 thousand years ago and is predicted to continue for many thousands of years. These predictions are based on the theory of Milankovitch cycles, a bit to complicated to explain here. It may last 50 thousand years, or even longer because of human interference (climate change!). After the interglacial, a new glacial will start, because Earth is still an Ice House.
Summary:
Earth is an Ice House already for 34 million years. An Ice House (also known as Ice Age) consists of many glacial (colder) and interglacial (warmer) periods, each lasting thousands of years.
The last glacial period occurred 26-20 thousand years ago and is often called the ICE AGE.
At the moment Earth is in an interglacial and that will last for many thousands of years, possibly even longer because of human interference.
Of course there is a lot of information available these days about future climate developments. Not always reliable !
Here is a very dishonest one, A New ICE AGE Is Coming: Prepare To Freeze By 2050! A lot of factually correct information, leading to a ridiculous ending. Click on the link to watch the video, AYOR!. His advice: Pump more greenhouse gases into the atmosphere to avoid the impending next Ice Age (~ 2050!).
It is generally assumed that you need liquid water for life to develop. The planet Mars is now dry and arid, but had lots of water in its far past.. The Perseverance rover (see my blog) is at the moment collecting samples of Martian soil, hoping to find fossil remains of (microbial) life, until now without results. Disappointing for those who are convinced that “simple” life must be ubiquitous in the universe.
When you have been following my blog, you will know that I am not really surprised. Personally I think that (simple) life will NOT develop easily, even in a suitable environment. See my recent post about the Drake Equation.
Are there other places in our solar system with (abundant) liquid water? Yes, there are, here are two, Europa and Enceladus. Europa is a moon of Jupiter and Enceladus a moon of Saturn. Europa is large with a diameter of 3122 km, only slightly smaller then Earth’s Moon (3475 km). Enceladus is much smaller, with a diameter of 504 km. In this image you see the relative sizes of Earth, Moon and Enceladus,
Here are the two moons, Europa left and Enceladus right.. Both moons are covered with a thick crust of water ice. This ice surface has a temperature of about -200 degree Celsius. But underneath this crust both moons have oceans of liquid water!
We think that the interior of the two moons look like this. Europa has a metallic core (iron and nickel),a rocky mantle and a (salty) ocean with an estimated depth of 60-150 km.. A thick ice crust ( 15-25 km) covers the ocean. The model shows the layers to scale.
Enceladus has a rocky core with radius of ~ 180 km , covered by a 30 km deep ocean. and a 20 km thick crust. The ice crust is thinner at the south pole.
How is it possible that these moons have liquid water under their ice crust? Where does the energy come from, the Sun is far way. The answer is: because of the tidal forces exerted by the giants Jupiter and Saturn on their moons.
Newton’s gravitation between two objects depends on the distance between them. For example the gravitational force exerted by the Moon on Earth is stronger on the side facing the Moon than on the other side. This difference is responsible for the tides. The tidal friction will slow down the rotation of Earth , so the length of a day will increase a little bit, about 1,8 millisecond per century. In the far past when the moon was born, the day length may have been about 4 hours only!, For the moon the story is similar: tidal friction has slowed it down, even a lot more, the Moon shows always the same face to Earth, it is “tidally locked”. Actually all the major moons in the Solar System are tidally locked to their planet.
Even tidally locked moons still can undergo tidal flexing, if the orbit is elliptical, a kind of kneading. Model calculations for Europa and Enceladus indicate that this .can generate enough energy to keep the oceans liquid. More (technical) details here.
So both moons have liquid water and a source of energy , two of the essential ingredients for life as we know it. The third ingredient (chemicals like carbon, hydrogen, nitrogen, oxygen, sulfur, and phosphorus) should be available in the rocky core.
The information about the two moons comes basically from two successful space missions. The Galileo spacecraft arrived at Jupiter in 1995 and stayed in orbit until 2003. It’s main mission was to study the planet, but it managed to have numerous flybys’ of Europa. The Cassini entered Saturn’s orbit in 2004 and stayed there until 2017.
The Cassini mission was very successful, click here for an overview. One of the most spectacular discoveries was that Enceladus is an active moon. There are geysers in the south polar region of the moon! This picture was taken by Cassini in February 2010.
The geysers consist of water vapor and ice particles. The explanation is that water seeps from the ocean floor into the rocky core where it is heated. The heated water rises and erupts though fissures in the icy crust.. It is a bit similar to the hydrothermal vents in Earth’s oceans.
There are indications that Europa also has this kind of geyser activity, although less intense Here is a recent (2021) NASA report, Are Water Plumes Spraying from Europa?
In the search for extraterrestrial life these two moons have top priority. Many proposals for missions to Europa have been formulated and later discarded, here is a list. At the moment the Europa Clipper is being prepared for a launch in October 2024. It will arrive at Jupiter in April 2030. Here is an artist’s concept, of Clipper, Europa and Jupiter. The solar panels of Clipper span 30 meter!
The artist impression might suggest that the Clipper will orbit Europa, but that is not the case, it will orbit Jupiter in an elliptical orbit and make 44 flybys of Europa. It will study Europa’s icy crust, find confirmation for the ocean underneath and try to make flybys through the geysers (if they exist).
A proposed follow-up mission is the Europa Lander. It would land on Europa, collect some material from the icy crust and search for biomarkers, signs of life. Here is another artist impression. Notice the geyser at the horizon 😉 .
Probably the Europa Lander mission will be cancelled. Why? Because Enceladus offers better options than Europa. The main difference is that Enceladus is continuously spewing water and ice crystals, whereas the geysers of Europa are sporadic and still have to be confirmed.
The reason that there is so much interest in the geysers is obvious. To find out if there is life in these oceans, we have to drill through a 15-25 km thick ice crust first. Actually there are studies how to do that, they read like science fiction. Here is the final report (pdf file, 70 pages, 2019) about the Europa Tunnelbot. The basic idea is that this tunnelbot would melt itself down through the ice crust of 20 km in 3 years time, to reach the ocean. Here is a artist impression from the report, I have rotated it 90 degrees, to fit better in this post. Left is the icy surface of Europa, the inset shows three “repeaters” because even when the bot reaches the ocean it still must transmit date to the lander.
Science fiction and I think it will never happen, because the geysers on Enceladus and possibly on Europa may already give information about life in the oceans below the crust!
After Cassini observed the geysers on Enceladus, the scientific program was adapted and the spacecraft went a few times through the plumes. It found water, ice crystals and organic compounds!
So that will be the program for the next decades, explore Enceladus and find out whether the geysers will have convincing biomarkers.. .
Of course it will take time to design Enceladus missions. Here is one, the Enceladus Orbilander. Approved as a so-called Flagship Mission. Still in the design phase. possible launch in the late 2030s Arriving at Enceladus in the early 2050s.
First it will fly numerous times through the geysers, collect material and analyse it. Then it will land at the South polar region.
This is the South polar region of Enceladus. The “tiger stripes” are fissures in the ice crust where geysers erupt.
And here is an artist impression of the Orbilander on the surface of Enceladus.
Until now life has only be found on Earth. Discovery of (primitive) life elsewhere in our solar system would be dramatic, because in that case we would know that (intelligent) life is ubiquitous in the universe.
At the moment Perseverance is collecting soil samples on Mars which will be brought back to Earth by the Mars Sample Return Mission around 2033. At about the same time Clipper will explore Europa. So we will have to wait for 10 years and for results from Enceladus about 30 years.
In 2019 I wrote a blog post A Pale Blue Dot with these two pictures in it. Left the iconic picture of Earth, taken in 1972 by the crew of the Apollo 17 spacecraft, on their way to the Moon. Right a picture taken in 1990 by the Voyager 1, leaving the solar system and looking back to Earth At 6 billion km only a pale blue dot.
Earth is our beautiful world, one of the eight planets in the Solar System and the only one where life has developed, as far as we know.
Are there other worlds in the Universe? Our Sun is one of about 100 billion stars in the Milky Way and the MIlky Way is one of an estimated 200 billion galaxies in the (observable) universe.
The left picture shows the spiral structure of the Milky Way, with the location of our Sun marked. The right picture is the famous Ultra-Deep Field image taken in 2003 by the Hubble telescope. The image shows an estimated 10.000 galaxies in a part of the sky with a diameter 1/10th of the moon.
In 1992 the first extrasolar planet (exoplanet) was detected, at the time of writing this blog more than 5000 have been found and it is now assumed that most stars will have at least one planet orbiting it. That means that in the Milky Way alone there are already billions of planets.
Wouldn’t it be strange if Earth is the only planet where (intelligent) life has developed? There could be numerous planets in the Milky Way and Universe where life has developed. Michio Kaku an American ‘science communicator’, who always enjoys being in the limelight, goes even further: “The Laws of Probability Tell Us That the Universe Should Be Teeming With Intelligent Life Forms”
The Laws of Probability ? As usual I am a sceptic. In 2010 I wrote two posts about “Are we alone in the Universe“. My personal opinion at that time was: “Yes, we might well be alone“. Now, thirteen years later, my opinion is still the same, maybe even stronger.
After this lengthy introduction, time to go back to the topic of this post, the Drake Equation.
Speculation about extraterrestrial life dates back to antiquity. Around 1900 it was thought by many that the planet Mars had irrigation canals, built by intelligent beings. Development of more powerful telescopes showed that those canals were an illusion. But maybe there were intelligent beings outside our solar system? This led in the 1960’s to the SETI program. the Seach for Extra-Terrestrial Intelligence. Involved in this program was Frank Drake, a young American astronomer. To have discussion points for the first scientific SETI meeting, he came up with what is now called the Drake equation.
Actually it is NOT an equation, it is an estimate for the number of intelligent civilisations in our Milky Way. The idea is simple, you start with how many stars are born yearly in the Milky Way. How many of these stars will have planets, how many of these planets will be suitable for life, how many of these suitable planets will actually develop life. How many planets with life will develop civilistations (intelligent life), and how many of these civilisations will be able/willing to communicate with us. And finally, how many years will such a civilisation survive.
Here the Drake equation is visualised: The estimated number of intelligent civilisations in the Milky way who can communicate with us is given by N as the product of a number of factors.
R* = how many stars are born every year in our galaxy. (R∗ = 1 yr−1)
fp = the fraction of these stars that have planets. (fp = 0.2 to 0.5)
ne = the average number of planets in the habitable zone of such a star (ne = 1 to 5)
fl = the fraction of habitable planets that actually develop life. (fl = 1)
fi = the fraction of those planets, where evolution leads to civilisations with intelligent life (fi = 1)
fc = the fraction of these civilisations that develop a technology capable of releasing detectable signs of their existence into space. (fc = 0.1 to 0.2)
L = the length of time that such a civilisation will exist.(L = 1000 -100,000,000 years)
In the 1961 discussion the various factors were discussed. I have given these estimates above. Using the lower limits, it gives a minimum of N ≈ 20 technological;y advanced civilisations, who could send signals to us. If those civilisations have not self-destructed, L could be many millions of years resulting in maximum of N ≈ 50.000.000 !
With this evaluation you will understand that it made sense to start the SETI program. After a few years a distributed computing project SETI@Home was started, where volunteers could use the idle time of their PC’s to analyse data from radio telescopes, searching for signals. of intelligent life . Many years I have taken part in this program. My PC during idle time was doing this.
After about 20 years the program was stopped, without any results. But in 2016 a follow-up project started Breakthrough Listen. Basically the same as SETI, but much more powerful, it will generate as much data in one day as previous SETI projects generated in one year. Until now no positive results.
I ended my 2019 post with :”As soon as evidence of life will be found, on Mars or deep under the frozen oceans of Jupiter’s moon Europa, I will celebrate and be convinced that life indeed is teeming in the Universe. Until then, I believe in the Rare Earth Hypothesis , that we might well be alone.“
What is this Rare Earth hypothesis? In 2000 Ward and Brownlee published a book Rare Earth: Why Complex Life Is Uncommon in the Universe in which they argue that primitive (microbial) life may be common in the Universe, but that complex (intelligent) life is probably very rare.
I agree with them that complex life will be rare in the Universe, but I no longer think that primitive life will be common.
A few months ago I published a post Perseverance perseveres about the Mars rover who is looking for traces of past life on the planet Mars. The scientists were expecting/hoping to find stromatolites, fossils of microbial life formed in the time that Mars had water. Something similar to this, found in Australia, 3.4 billion year old.
Stromatolithe – MNHT
Until now no sign of fossil microbial life has been found. So it could be that the chance that primitive life develops on a planet in the habitable zone is also small!
As long as no sign of (fossil) microbial life is found in our solar system or elsewhere, I think that even primitive life may be rare in the universe. I used to say, We may be alone in the Universe. I now go one step further:
On 18 February 2021 the Perseverance rover landed successfuly in the Jezero crater on planet Mars. A few weeks later I wrote a detailed blog about the landing and the mission of the Perseverance: to determine whether Mars ever was, or is, habitable to microbial life. We are now more than two years later, time to give an update. I assume that you have read the first post ;-).
First about the Ingenuity helicopter. There has been a lot of opposition to include the helicopter in the project, many people were worried that it might compromise the main goal of Perseverance. Here are two pictures taken by the WATSON camera (mounted on the robotic arm). Left the Ingenuity still under Perseverance’s belly with its legs unfolded, right next the the rover, ready to fly. Photos taken 1 and 7 April 2021, respectively
Here is a selfie of Perseverance, taken on 6 April 2021 again by the WATSON camera. Notice how small the helicopter is. Do you wonder why you don’t see the robotic arm in this picture? Actually WATSON took 62 pictures, resulting in this composite image, click here for details.
Originally only 5 flights of Ingenuity were planned, just to test if the helicopter could fly in the very thin Martian atmosphere. Because contact with Earth takes about 11 minutes, those flights have to be autonomous. They were so successful that the Ingenuity is still operating now, on 23 April it had its 51th flight. It is actually scouting for Perseverance to find suitable locations to explore. Click here for a list of all flights, full of interesting details. During flight 51 Ingenuity took a picture of Perseverance (upper left corner). Not easy to spot, the right picture shows an enlargement
In my Perseverance blog, I could only be rather vague about details of the mission. The rover was supposed to collect samples of Martian rocks and soil (regolith), using the drill on its robotic arm. Then put these samples in sample tubes and store them in a container. Here is an example of a sample tube, the container can hold 43 of them.
Here is the proposed route at the time when I wrote my blog.. The x marks the landing of Perseverance in the Jezero crater, which was a lake, billions of year ago. In those days a river was flowing into the lake (from the left), creating a delta of sediment. If ever life developed on Mars, this region might be suitable to find proof of it.
And here you see the actual route of the rover during the last two years. It is a screenshot from the NASA website Where is Perseverance? Really worthwhile to visit the site, you can zoom in on the map which is updated regularly. The red markers give the locations where samples have been collected. The blue markers show where the Perseverance and the Ingenuity are.
When you visit the website and zoom in, you will get this. Clicking on a white circle will tell you when the rover was there, clicking on a line segment gives the distance, clicking on a red marker will tell you the number of the sample collected
During the two years that Perseverance has been exploring, it has collected 19 samples, here is the list, with lots of details for each sample.
The first sample was actually a failure, it must have been a shock for the team! Here is a screenshot. Sample Type: Atmosopheric. The core must have been too powdery/brittle, broken into pieces, and the capsule is empty. More about it here .
Fortunately all other sampling attempts until now were successful. Here is an example. The rocky outcrop has been named Wildcat Ridge. Two samples (no 12 &13 in the list) have been drilled and a circular patch of the rock has been abraded to investigate the rock’s composition.
Why two samples from the same location? When you look at the list, you will find that this is the usual procedure. All samples have been collected twice from each location (except the first, failed, one).
In the period between 21 December 2022 and 28 January 2023, one sample of each location has been dropped in what has been called a depot, named Three Forks. I have indicated the location with a red oval in the detailed map above. Here is a picture of the second sample being dropped.
And here is a collage of all 10 samples dropped. THe Atmospheric sample, 8 samples with rock or regolith and one witness sample. A witness tube will follow the same procedure, but not collect any rock or regolith. Back on earth it will be inspected to check for any contamination with material from Earth. Click here for more details.
,The sample tubes tubes are not dropped at the same spot, but about 5-15 meter apart. The center of each circle is the location where that sample was deployed, with in red the name given to the sample (see the list).
Why all this? Basically for safety reasons. The ultimate goal of the mission is to bring the sample capsules back to earth, where they can be studied in much more detail than is possible by Perseverance. In my first blog I wrote that this so-called Mars Sample Return porjectat first sight looks like science fiction. And I still think it does 😉 . Here is an outline of the project in its present form.
In 2027 the Earth Return Orbiter (ERO) will be launched and reach Mars in 2029 where it will go in orbit and wait for the container with the samples.
In 2028 the Sample Retrieval Lander (SRL) will be launched. It will land on Mars in 2029, probably close to the Three Forks depot. It will bring two helicopters and the Mars Ascent Vehicle (MAV), a rocket.
If Perseverance is still working properly, it will also travel back to the Three Forks depot. In that case it can transfer its samples to the MAV
If not, the two helicopters will transfer the ten dropped samples to the MAV
After the samples have been stored in the MAV, it will leave Mars, go in orbit around the planet and release the container with the samples.
The ERO will pick up the container with the samples and place them in the Earth Entry Vehicle (EEV). Then it will leave its orbit and travel back to Earth
Near Earth the ERO will release the EEV which will “fall” back to Earth. No navigation, no parachute. It is scheduled to land in 2033 in the desert sand of the Utah Test and Training Range.
In this artist impression the Sample Retrieval Lander is at the right, left the Perseverance. The Mars Ascent Vehicle has just been launched, it will bring the container with the precious samples to the Earth Return Orbiter. One of the Sample Recovery Helicopters is hovering in the thin Martian atmosphere.
In the original design, the Sample Retrieval Lander carried another rover which transported the sample tubes from Perseverance to Mars Ascent Vehicle. . It has been skipped because of the success of the Ingenuity helicopter. The Sample Recovery Helicopter has basically the same design, but is stronger, can carry a small load and has wheels. Here is an artist imprssion. It can transport a dropped sample tube, one at a time, from the depot to the Lander.
.Another design change is that the Sample Retrieval Lander has a powerful robotic arm to put the samples in the sample container. Have a look at this fascinating video. The robotic arm picks up a sample tube from the ground, and puts it inside the rocket. But it can do the same with samples stored inside the Perseverance.
Have a look at this animation. You see the Sample Retrieval Lander land near the Perseverance. The robotic arm transfers the sample capsules to the Mars Ascent Vehicle, which is then launched. When in orbit it releases the container with the samples. This container is then collected by the Earth Return Orbiter. There the container will be placed in the Earth Entry Vehicle. All this will take place after the landing of the Sample Retriever Lander in 2029.
At the moment the whole whole retrieval mission is still in the design phase. Here are prototypes of the sample container and the Earth Entry Vehicle. To give you an impression of the size, a sample tube is about 15 cm long. The container is roughly the sise of a basketball. The diameter of the EEV will be about 1.5 meter.
The retrieval operation will take place in 2029, six years from now. The Perseverance is working beyond expectation, but will it still work properly in 2029? In the first phase of the exploration Perseverance has collected dupilcate samples and dropped one of each at the Three Forks depot. In one of the NASA reports I read that in the second phase the Perseverance will no longer collect duplicates.
So, when everything goes well, in 2029 Pereverance will return to the Three Forks Depot with in its belly around 30 collected samples. In that case The Robotic Arm will transfer the samples to the sample container. It will leave the depot untouched! Why? Because the retrieval will be a risky process. The container after launch will be floating in orbit and hopefully collected by the Earth Retrun Orbiter. And near earth the container, now inside the EEV, will be dropped near Earth and hopefully fall down in the Utah desert. I still think it’s science fiction 😉 So, in case something goes wrong, at least there are still 10 samples in the depot, waiting for another mission.
The paragraph above is my own interpretation.
And this is my personal comment, before I finish this blog.
The whole mission until now has been presented as a huge success. And techologically speaking, I agree. But still I think the scientists will be a bit disappointed, because a “smoking gun” has not been found until now.
When (microbial) life developed on earth, 3.5 billion year ago, it left fossil traces behind, called stromatolites, like this one, found in Australia..
Stromatolithe – MNHT
If this kind of sediment would be found in the Jezero crater om Mars, it would be frontpage news all over the world: Life has existed on Mars.
In 2019 a team of NASA/ESA scientists went to Australia to study the stromatolites. In the video they call them the Holy Grail.
But until now no sign. The collected samples contain organic molecules, but that is nothing new, Curioisity, the predecessor of Perseverance already found them.
Of course Perseverance will persevere exploring the sediments in the Jezero delta and collect more samples. Hopefully it will one day be able to take pictures of stromatolite. If not then we will have to wait until 2033 when the samples are returned to Earth and can be investigated in specialised laboratories.
Yes, I think the scientists are a bit disappointed.
