Supermoon, 14 November 2016

Just a short post about the Supermoon of 14 November, widely publicised by the media the last few weeks as a not to be missed, once in a lifetime event. For example on Facebook

It’s a hype.

Supermoons are not rare, they occur regularly, on average every 14 months. The last one was 28 September 2015, the next one will be 4 December 2017.

Full moons have different sizes because the orbit of the moon is slightly elliptical. The image shows the moon orbit, exaggerated. The average distance to Earth is 385.000 km, but the moon can come as close as 356.500 km (perigee) and as far as 406.700 km (apogee). The moon orbit also rotates itself with a period of 8.85 year

lunar-phases-elliptical-orbit

As a result of these two effects, a full moon can sometimes occur when the moon is in or near its perigee. An observer on Earth will then see this full moon brighter and larger, than when it occurs in its apogee. Dividing the apogee distance by the perigee distance, we find 406.700 / 356.500 = ~ 1.14, so the moon will look ~14 % brighter and ~ 30 % larger. This effect is easily observable, as you can see in the image below.  By the way, the name Supermoon has been introduced by astrologers, the correct name is Perigee Full Moon.

mini-supermoons-of-2015

So, why this sudden interest in this particular Perigee Full Moon of 14 November?

The values given for apogee and perigee are actually averages. Because of the influence of sun and planets they vary slightly in time. Here are the perigee distances during the Supermoons of 2015 and 2016 :

  • 356.876 km in 2015
  • 356.511 km in 2016

The perigee distance on 14 November is a little bit smaller! To be precise , 365 km smaller, ~0.1%. So the Supermoon of 14 November will be 0.1% brighter and 0.2% larger. Observable for the unaided eye? Not at all, believe me…:-)!

Why the hype?  When you look at the Perigee Full Moons in the past and future, you  have to go back to 1948 to find an even smaller full moon perigee: 356.462 km (49 km smaller).  And from now on you have to wait until 2034 to find a smaller one: 356.447 km (64 km smaller). These Supermoons will be ~0.02 % brighter.

That’s why it is said: the brightest Supermoon in 86 year…:-). Technically correct, but….   a hype.

My suggestion, try to observe the moon tomorrow, when it is rising, just after sunset. The moon looks always larger when close to the horizon! This is an optical illusion, the Moon Illusion. Combined with the Perigee Full Moon it will be beautiful

And when you are not free tomorrow, it is not that critical. One or two days later you can still admire the Supermoon.

Our nearest neighbour?

As you may know from my  blog, I think we may be alone in the Universe. But of course I would be more than happy if (intelligent) life would be found outside our own planet. My PC is taking part in the SETI project, see my blog  Anybody out there? Last week there was excitement about a strong signal from a sunlike star, but: No alien signal, says SETI astronomer.

Numerous extrasolar planets have been found by now, as of 1 September 2016 the count was 3518. A few dozen of them might be able to support life (rocky, similar size to Earth, orbiting in the habitable zone of their star).

So, why did this Letter to Nature (one of the leading science magazines) :  A terrestrial planet candidate in a temperate orbit around Proxima Centauri cause so much commotion that it became front page news in the media?

The answer is simple: Proxima Centauri is not just one of the hundreds of billion stars in our galaxy. It is the star closest to our Sun, at a distance of 4.22 lightyear “only“,

Let’s have a closer look at this nearest neighbour of the Sun.  Where can we find it in the night sky? And can we see it  with unaided eyes or binoculars?

Here is the night sky (in Malaysia) in March, south-eastern direction. You will notice three constellations, dominated by Centaurus. The name comes from Greek mythology, where a Centaur is a half-horse half-man creatureSky-march

centaurus_contellation

Here is how the Greek saw a Centaur in the stars.

You may find it difficult to see a centaur, but the two bright stars in his left leg are conspicuous. Rigel Kent, better known as α Centauri, is the third-brightest star in the sky, after Sirius and  Canopus. 

Hadar (β Centauri) is also a bright star.

α Centauri is actually a star system, consisting of three stars. Two of them, α Centauri A and B are so close that they can not be separated by the unaided eye. Here is an image taken by the Hubble telescope.

Best image of Alpha Centauri A and B

 

α Centauri A (to the left) is slightly larger than the Sun, while B is a bit smaller. They orbit around each other with a period of 80 years.

 

 

The third component, α Centauri C is a red dwarf, much smaller and cooler (more reddish)  than the Sun. Very far away  (about 0.21 ly) from the other two. If it is bound by gravitation to A and B (not 100% sure), the estimated orbiting period is ~ 500.000 year. Here are A and B (seen as one star here) and C (in the center of the red circle). The other stars are Milky Way stars, much farther away.

The α Centauri system is closer to the Sun than any other star, about 4.35 ly away, and of the three components, α Centauri C is a bit closer (4.22 ly) and therefore it has been named Proxima Centauri.

Because of the close distance, the system has been studied intensively. A planet might be orbiting α Centauri B, but even if found to be true, it will not be habitable.

 

Now a planet has been found, orbiting the red dwarf in the α Centauri system. It has been called Proxima b. Very close to the star, orbiting it in about 11 days only. Compare this with Mercury’s period of 88 days. But because the star is less bright than the Sun, the planet is still in the habitable zone. Here is an artist impression how the planet could look like. α Centauri A and B are also shown, as bright stars.

Artist's_impression_of_the_planet_orbiting_Proxima_Centauri-002

Our closest neighbour! But a distance of 4.22 light-year means that Proxima b is still 40 trillion km away from Earth. At this moment spacecraft New Horizon, after taking spectacular pictures of dwarf planet Pluto, is leaving our solar system with a respectable speed of ~ 60.000 km/h. That is fast, but it would take ~ 80.000 year to reach Proxima b.

Here is what the Mail Online reported on 24/8. “The second Earth that we could visit in our lifetime”  and  “just four light years away

Actually there is an audacious plan to send a probe to Proxima b. Not a spaceship but a space-chip! Not one probe, but a swarm of them. Interested?  The project is called .Breakthrough Starshot and it deserves a separate blog post.

Here only a few comments on the idea of a “second Earth”.

  • As the planet orbits very closely to its Sun, it will probably be tidally locked, like Mercury. In that case the sun side will be scorching hot, the other side dark and freezing cold. Only the twilight zone might be able to support life
  • Proxima Centauri is a flare star, with occasional eruptions of radiation, comparable but much stronger than the solar flares. Not very suitable for the development of life.
  • Will there be water on Proxima b?  Earth got its water during the Late Heavy Bombardment. when numerous comets and asteroids, disturbed in their orbit by the giant planets, collided wit Earth.

In this very readable Scientific American blog more skeptical arguments are given.

Here are a few other habitable planets. Proxima b is not yet in this list, it belongs to the bottom row, Proxima Centauri is a so-called M star

Kepler-452b (top row) is sometimes nicknamed Earth’s Cousin..:-) But the distance to Earth is a whopping 1400 light-year!  It would take New Horizon about 25 million year to go there.

More about the Breakthrough Starshot project in a later blog post

Our Solar system, an update

My last blog about the Rosetta, Dawn and New Horizon missions was posted in July last year. Before I give an update, let’s first have a look at our Sun. Here is a recent graph of the number of sunspots. Cycle 24 has reached a maximum in April 2014 and is coming to an end.

cycle_24

As you will notice, cycle 24 has a double peak, in itself not unusual, but this time the second peak is higher than the first one. The maximum of cycle 24 is much smaller than that of cycle 23, and the prediction for cycle 25 is that it will be similar to cycle 24 or even smaller.

Here is a graph of the sunspot cycles, recorded until now. It looks like we have passed the Modern Maximum and are going to a minimum. Are we heading to a new “Little Ice Age“?  As I wrote in an earlier post, this is a sensitive issue, and I will not comment on it..:-). Be very wary when you search the Internet for info  about a relation between solar activity and global warming. Always check the credentials of the report. You might try this site: Skeptical Science

Sunspot_Numbers

Here is a dramatic image of our Sun, taken by the Solar Dynamics Observatory. Magnetic field lines are superimposed.

3238931400000578-3493882-image-a-019

Rosetta

Rosetta is still orbiting comet 67P, which has passed its perihelion and is now on its way out into deep space. Here is the position of Rosetta and the comet, end of last year, the comet has passed already the orbit of Mars. No signals of the comet lander Philae have been received anymore, but Rosetta itself is still active.

Rosetta

Here is a recent image of 67P, taken on 27 March, when Rosetta was 329 km away from the comet nucleus. The Sun is behind the comet, with a spectacular result.

cometon27march2016navcam

The scientists are planning to let Rosetta make a controlled landing on 67P in September 2016, which will be the end of the mission. You can find the latest news on Rosetta’s blog

Dawn

Dawn is still in orbit around dwarf planet Ceres. Slowly getting closer, resulting in more detailed pictures. You may remember the excitement about the bright white spots. Now we know that they are located in the center of a crater, which has been given a name: Occator. More (smaller) white spots have been found

Occator_PIA19889

Here is the most recent picture (in false color), taken 30-3-2016 from an altitude of 385 km. . Spectacular. Scientists now think that the white spots are formed by highly reflective material, possibly ice or salt.

Occator

Actually Dawn is taking pictures of the whole surface of Ceres. Scientists have been busy giving names to the various features..:-)

Ceres mapping

For more information about Dawn, read this detailed blog So.Much.Ceres, published a few weeks ago

New Horizons

On 14 July 2015, the New Horizons spacecraft passed Pluto at an altitude of 12.500 km above its surface. It took as many pictures during the fly-by (of only a few minutes!) as possible and it still has not finished transmitting all the data to Earth!

Here is one of the images, released a few days ago. It shows numerous “haloed” craters. The false-color image gives the composition: purple is methane ice, blue is water ice. Why the crater rims and walls consist of methane ice has not yet been explained.

Craters on PLuto

New Horizons is now on its way to the Kuiper Belt, where it is supposed to flyby one of the Kuiper Belt objects, 2014 MU69 , on 1-1-2019.  Here are the present locations of the New Horizons spacecraft and 2014 MU69

New_horizon

Planet 9

We have reached the outskirts of our Solar System. Pluto, once the 9th planet, has been demoted and is now considered a dwarf planet belonging to the Kuiper belt. Recently more dwarf planets have been discovered in the region beyond Neptune,  Eris ( in 2005) , Haumea (in 2004) and Makemake (in 2005)  Like Pluto they have quite elliptical  orbits and periods in the range of a few hundred years. Pluto for example has a period of  248 year and its distance to the Sun varies between 30 and 49 AU, where 1 AU (the average distance between Earth and Sun) = 150 million km. The orbits of these dwarf planets have been strongly influenced by big neighbour Neptune.

In 2003 dwarf planet Sedna was discovered with an estimated period of 11.400 year and a distance to the sun varying between 76 and 936 (!) AU. Here is the orbit of Sedna. Pluto’s orbit is purple.

Sedna

What could have caused such an extremely elliptical orbit? It can not have been gravitational disturbance by Neptune, because it never comes close to Neptune (distance of Neptune to the Sun is 30 AU).

In the last decade more of these “strange” objects have been discovered. For example in 2012  2012 VP113, estimated period 4200 year, distance to the Sun between 80 and 438 AU, also very elliptical.  Here the orbits of six of them are given.

TNO

Could these orbits be gravitationally disturbed by an UNKNOWN planet in the outer reaches of the Solar system?

On 20 January 2016 astronomers Brown and Batygin published an article in the Astronomical Journal: Evidence for a distant giant planet in the Solar System (abstract). Using computer models, they find that a planet with a mass about 10 times the mass of Earth, a period of 10.000-20.000 year, and a distance to the Sun varying between 200 and 1200 AU, could explain the orbits. Tentatively this planet is named Planet Nine .

Here is a sketch with the position of this Planet Nine.

Planet_Nine_-_black_background

Of course this is a hypothesis until now. Other explanations are possible. Next step is to try and find Planet Nine. That will not be easy, even for the most powerful telescopes. And where to look for it?

Here is a picture of the two authors, both astronomers from Caltech. By the way, Brown (left) is  the guy who discovered Eris, which started the demotion process for Pluto!

Brown & Batygin

They have started a website The Search for Planet Nine and just submitted a (highly technical) paper in which they discuss where to search for this planet.

If Planet Nine is ever found, I will not be surprised if they get a Nobel Prize for their research.

The Largest Prime Number

On 7 January 2016 a “new” large prime number was discovered, with more than 22 million digits. Time for a blog about these numbers, which have fascinated mathematicians from Greek antiquity until present times.

Prime numbers are numbers that can only be divided by 1 and itself. For example 7 is a prime number, but 6 is not because it can be divided by 2 and 3. . Here is a list of the 168 prime numbers smaller than 1000. The number 2 is the only even prime, all others are odd.

prime-numbers

How many prime numbers are there?

Euclides

Euclides, the famous Greek mathematician, living in present-day Egypt  around 300 BC, already proved that their number is infinite, and his proof is so elementary, that I often presented it to my students when I was a teacher, as an example of what is called Reductio ad Absurdum.

Euclides’ proof:  Assume that you have a complete list of all prime numbers.

  • Multiply them together and add 1. Call this number X.
  • Because of the added 1, this number X can not be divided by any prime number in your list (there will always be a reminder 1)!
  • So there are only two possibilities, either X is prime itself, or it can be divided by a prime number outside your list. In both cases it shows your list was incomplete.
  • Therefore our assumption was wrong and the list of prime numbers is infinite!

How to find out if a number X is prime?   Do we  have to check whether X is divisible by any number, smaller than X ? That would be a tedious job. Fortunately it is not as bad as that…:-). Because it is easy to see that we only have to check whether X is divisible by any prime number, smaller than the square root of X.

For example X=283, is it prime? The square root of 283 = 16.82…, so we have only to check division by 2,3,5,7,11 and 13.

  • 283 / 2 = 141 rest 1
  • 283 / 3 = 94 rest 1
  • 283 / 5 = 56 rest 3
  • 283 / 7 = 40 rest 3
  • 283 / 11 = 25 rest 8
  • 283 / 13 = 21 rest 10

So 283 is a prime number!

This procedure is called Trial Division. For large numbers it becomes time consuming. For example, we want to check if 1000.003 is prime.  There are 168 prime numbers smaller than 1000, so we have to do 168 divisions to finally conclude that, yes, 1000.003 is prime. Repeating this procedure for 999.997, you will find that this number is not prime, it can be divided by 757.

Imagine that you have to do these divisions with only pen and paper!

Back to the recently discovered large mega-prime. It is a so-called Mersenne prime, one less than a power of 2:  Mp = 2p − 1 with p itself a prime number.

  • M2 = 22 − 1 = 4 – 1 = 3 prime!
  • M3 = 23 − 1 = 8 – 1 = 7 prime!
  • M5 = 25 − 1 = 32 – 1 = 31 prime!
  • M7 = 27 − 1 = 128 – 1 = 127 prime!

Could this be a rule to create prime numbers? Unfortunately that is not the case.       M11 = 211 − 1 = 2048 – 1 = 2047 = 23 * 89 , not prime!
However the next one M13 = 213 − 1 = 8192 – 1 = 8191 is again prime.
As are M17 = 131.071 and M19 = 524.287. The last two are already quite large, in 1588 the Italian mathematician Cataldi had proven by trial division that they were prime.

Why are these numbers called Mersenne primes?

Marin_mersenne

Marin Mersenne was a French priest with an interest in mathematics, theology and philosophy.

He published in 1644 a list of these numbers 2p − 1, stating that they were prime for p  = 2, 3, 5, 7, 13, 17, 19, 31, 67, 127 and 257, and not for any other p below 257.

His list was incomplete and incorrect, but still these prime numbers carry his name…:-)

Incorrect, because M67 and M257 are composite
Incomplete, because M61 , M89 and M107 are prime

Mersenne was correct that M31 = 2.147.483.647 is prime, but how could he know? This is a big number, the square root is ~ 46.340, so he should first determine all prime numbers smaller than 46.340  (there are 4792) and then perform trial division for all those 4792 numbers. It must have been a lucky guess. And certainly it was a guess for M127 = 170.141.183.460.469.231.731.687.303.715.884.105.727 🙂

18th century mathematician Leonhard Euler

It was only in 1772, more than a century later,  that the great mathematician Leonhard Euler proved the primality of M31.

By a clever analysis of the general structure of Mersenne numbers, he managed to reduce the number of trial divisions to 84 !

Still a big job (pen and paper), the story is that he had a team of helpers to do the actual calculations.

This was the last result using trial division. For more than a century no developments regarding Mersenne primes took place.

Elucas_1

Until 1857, when Édouard Lucas, a young French boy (15 years old), gets interested to prove that M127 is prime.

As trial division is not feasible for these large numbers, he studies the structure of the Mersenne numbers and develops a method to check the primality without trial divisions.

After 19 (!) years of testing his methods, he is convinced and announces in 1876 that M127 is prime. The 9th Mersenne prime!

His approach, later refined by others, is still used in the search for new Mersenne primes. Characteristic for this Lucas–Lehmer primality test is that it can decide that a Mersenne number is NOT prime, without finding the factors of this number. For example, using this test, we find that M257 = 231.584.178.474.632.390.847.141.970.017.375.815.706.539.969.331.281.128.078.915.168.015.826.259.279.871 is composite, but we don’t know its factors…:-)

With Lucas’ method, in the following years/decades the primality of M61 , M89 and M107 is proven. Still using pen and paper!

New activity starts only in the 20th century when the first computers are built.

SWAC_001

One of them is the famous SWAC computer, built in 1950. Nowadays a PC or even a tablet would be more powerful.

In 1952 it was used to check new Mersenne primes. Within one year 5 new ones were found, for p = 521, 607, 1279, 2203  and 2281. Still using the methods developed by Lucas

Very large numbers! Here is prime number M2281 with 687 digits. To make it more readable, spaces have been inserted after three digits.

446 087 557 183 758 429 571 151 706 402 101 809 886 208 632 412 859 901 111 991 219 963 404 685 792 820 473 369 112 545 269 003 989 026 153 245 931 124 316 702 395 758 705 693 679 364 790 903 497 461 147 071 065 254 193 353 938 124 978 226 307 947 312 410 798 874 869 040 070 279 328 428 810 311 754 844 108 094 878 252 494 866 760 969 586 998 128 982 645 877 596 028 979 171 536 962 503 068 429 617 331 702 184 750 324 583 009 171 832 104 916 050 157 628 886 606 372 145 501 702 225 925 125 224 076 829 605 427 173 573 964 812 995 250 569 412 480 720 738 476 855 293 681 666 712 844 831 190 877 620 606 786 663 862 190 240 118 570 736 831 901 886 479 225 810 414 714 078 935 386 562 497 968 178 729 127 629 594 924 411 960 961 386 713 946 279 899 275 006 954 917 139 758 796 061 223 803 393 537 381 034 666 494 402 951 052 059 047 968 693 255 388 647 930 440 925 104 186 817 009 640 171 764 133 172 418 132 836 351

IBM_7090_computer

Computers became more powerful, and new Mersenne primes were discovered. In 1961 the first Mersenne prime with more than 1000 digits was found, M4253, using an IBM 7090 mainframe computer (pic left)

And in 1979 the first Mersenne prime with more than 10.000 digits was found, M44.497, using a Cray supercomputer.

You might expect that the recently discovered Mersenne prime M74.207.281 with more than 22 million digits has been found using a super-super computer…:-)  But that is not the case! Actually PC’s were used, not one but many, working together!

In 1996 the Great Internet Mersenne Prime Search ( GIMPS) project was started. It is an example of what is called  distributed computing.  A PC will often be idle, so why not  let it work during that time for a project such as GIMPS. Just download some software and your PC will try to find a new Mersenne Prime. Many thousands of volunteers are doing this. And with success

Since 1996, 15 new Mersenne primes have been found, all of them using GIMPS!

Of course finding a new Mersenne prime has no scientific value, it is just an intellectual challenge. But you might win a prize!

When in 1999 the first Mersenne prime was found with more than 1 million digits,M6.972.593 , the Electronic Frontier Foundation awarded this result with a prize of 50.000 US$. In 2008 M37.156.667 was found, with more than 10 million digits. The award was 100.000 US$

Two more prizes have not yet been awarded

  • 150.000 US$ to the first individual or group who discovers a prime number with at least 100 million digits
  • 250.000 US$ to the first individual or group who discovers a prime number with at least  1 billion digits

The latest Mersenne prime M74.207.281 has 22.338.618 digits, not yet enough for the next reward

So, why not join GIMPS!  I did….:-)

For this blog I have made extensive use of The Prime Pages

Large numbers have been calculated using the Online Big Number Calculator

The End of the World? Not again, please!

The last End of the World was predicted for 21-12-2012, the end of the Mayan calendar. Earth would be destroyed by an asteroid, Nibiru, or some other interplanetary object, an alien invasion or a supernova. Nothing happened.

mayan-cartoon-astrology-quote

End October 2012 I created a special homepage for my website stuif.com with a counter keeping track of the time until the apocalypse. Have a look..:-)

This counter is still counting, now almost 1000 days later.

Maybe I it is time to design a new homepage…:-;

So what about the next End of the World?

 

The next apocalypse prediction has a “Christian” background and should take place between 15 April 2014 and 28 September 2015. I have written “Christian” in quotes because it is not mainstream Christianity. Heavily leaning on its Jewish roots, “evangelical”,  often considering the Catholic Pope as the Anti-Christ.

Why these dates? It has to do with lunar eclipses.

Time for a short astronomical intermezzo.

A lunar eclipse occurs when the moon passes through the shadow of Earth. If the moon’s orbit would be in the same plane as Earth’s orbit around the Sun (called the ecliptic) , this would happen every month, during full moon. But the orbital plane of the moon is tilted ~5 degrees respective to the ecliptic. Without going into details, as a result a lunar eclipse doesn’t occur monthly, but on average every six months. And it is not always a full eclipse, sometimes it can be partial, with part of the moon still lit by the Sun.

When the eclipse is complete, you would expect the moon to be completely invisible. But that is not the case! Here is a beautiful composite picture taken during the lunar eclipse of 15-4-2014, taken in Las Vegas, USA. During full eclipse the moon is still visible but reddish!

o-BLOOD-MOON-PHOTOS-900

The explanation is “basic” physics. It is because the sunlight  is blocked by Earth, but not fully by the Earth atmosphere. The blue part of the sunlight is absorbed (causing our  blue skies!), but the red part is let through, still reaching the moon, even during eclipse. Sometimes people call it a “blood moon“.

Back to the End of the World prophesy.

The Bible contains several prophesies about the apocalypse, the “Day of the Lord” . For example in the Old Testament, Joel 2:31:

The sun shall be turned into darkness, and the moon into blood, before the great and the terrible day of the LORD come.

Apparently we have to look for solar eclipses and lunar eclipses! But both eclipses occur 2-3 times each year! Here is the list for 2014 and 2015. Notice that solar eclipses are only visible in a very limited region of Earth, compared with lunar eclipses. Also notice that a solar eclipse always falls two weeks before or after a lunar eclipse.

eclipses

One feature is a bit special: all four lunar eclipses are total and will result in a blood moon. Such a tetrad of lunar eclipses is not common, but also not rare, you can check it yourself on this very informative eclipse page

Time to introduce John C. Hagee, founder and Senior Pastor of Cornerstone Church in San Antonio, Texas, a non-denominational evangelical church with more than 20000 active members.

He received a Bachelor of Science degree from Southwestern Assemblies of God University in Waxahachie, Texas, which may explain his interest in astronomy. Prolific writer. In 2013 he published “Four Blood Moons”, a NYT bestseller

PastorJohnHagee_resized

81-N5LZB1GL

John Hagee does not like Catholics and considers Obama to be the Anti-Christ. He is founder and National Chairman of Christians United For Israel. Very significant for him is that the eclipses in 2014 and 2015 coincide with Jewish holidays.

blood-moons

Is that really so remarkable? The Jewish calendar is a lunar calendar, with festivals generally on New Moon or Full Moon!

So, according to John C. Hagee, on 28-9-2015 the Great Tribulation will start! Repent! I am wondering how he and his family will spend that day..:-)

If nothing happens, you will have to wait for the next End of the World. Here is a list of predictions. The scientific prediction may be the most reliable: in about 5 billion years, our Sun will develop into a Red Giant star and absorb Earth.

Interested in this topic? Do a Google search for Blood Moon Apocalypse and you will get numerous hits. But be prepared for a lot of “rubbish”. Like for instance this youtube clip

Close encounter with Pluto

In an earlier post, Close Encounters , I mentioned three memorable astronomical events in 2015. One of them was the flyby by the New Horizons spacecraft of the (dwarf) planet Pluto on 14 July at 11:49:58 UTC  (7:49:58 pm Malaysian time)

One day earlier, when the New Horizons was still a respectable 800.000 km away from Pluto, it took this picture.The heart-shaped region, the smooth surface, caused already much excitement

Pluti

New Horizons was approaching Pluto at a speed of ~ 50.000 km/h, so the flyby was near. At this high speed the observation window for taking close-up pictures was narrow. It was decided to stop communicating with the spacecraft during the flyby, as the on-board computers would be busy collecting data. There was a lot of tension in the control room during the blackout. Here is the response when the first signal of New Horizons after the flyby is received. Mind you, it takes about 4.5 hours for light and radio signals  to cross over form the spacecraft to Earth, as the distance to Pluto is about 5 billion km at the moment.

CJ6qO7RWoAAyzFQ-1

This first signal was only a sanity signal that everything was working normally. Transmission of the images is a time-consuming process. It was only the next day that NASA published the first detailed image. nh-pluto-surface-scale

Many surprises. The surface looks very smooth, scientists think it can not be more than a few hundred million year old. Has Pluto still an active interior? And there are mountains, up to 3 km high. They might consist of water ice.

A second picture has been published today, details of Pluto’s (principal) moon, Charon.

CHARON GRAPHIC 7-16

More excitement. Impact craters here, but what is this strange feature in the top left corner? More pictures will arrive and hopefully be published in the coming days. But the analysis will take months if not years.

New Horizons has done a marvelous job. It will now pass through the Kuiper Belt and leave our solar system. You can follow the spacecraft on the New Horizons website

What about the two other events?

Dawn has successfully entered orbit around Ceres and is still observing the asteroid. The white dots on its surface have not yet been explained. Here is a collage of images taken by Dawn. The Dawn Blog is still online and active

Dawn

Finally Rosetta and Philae

Rosetta is still orbiting comet 67P, which is now on its way to perihelion, the closest distance to the Sun. Perihelion will be reached on 13 August. Already the comet is feeling the heat of the Sun and partly evaporating. This picture was taken on 7 July

ESA_Rosetta_NAVCAM_20150707_enhanced

Mixed news about Philae. There was huge excitement when it came out of hibernation on 13 June and “talked” for a few minutes with Rosetta. But after that, communication has been intermittent, for reasons unknown. However, ten days ago, Philae has contacted Rosetta again and actually transferred data from one of its on-board experiments! The scientists are hopeful that it will get more active the next few weeks. Read more on the Rosetta/Philae blog

I will update this post when more  news/pictures become available

Update 18-7-2015

Yesterday NASA published another picture, a detail of the heart-shaped area , which has been provisionally named Sputnik Plain. Some features have been identified. This icy plain can not be more than 100 million old. More details here

04_moore_02c

Anybody out there?

When you have followed my blog posts, you will know that I am a supporter of the Rare Earth Hypothesis. Mind you, I will be more than happy if  proof of extraterrestrial life is found, but for the time being, I think we may well be alone in the Universe..:-(

Actually, for many years already I am participating in the SETI@home project. SETI stands for Search for ExtraTerrestrial Intelligence. The purpose of the project is to analyse radio signals for signs of intelligent life in the universe, and it is doing this by what is called distributed computing. The data to be analysed come from the Arecibo radio telescope in Puerto Rico.

More than 120.000 PC’s all over the world take part, my PC is one of them. When my computer is idle, it starts analysing a data packet received from Arecibo. Results of the analysis are sent back to SETI, I receive a new data packet and so on…:-)  Here is the Arecibo telescope (with its mirror diameter of 300 m the largest in the world) and a screenshot of my monitor while it is analysing the data. Visual output is a screen saver, moving around the screen all the time..

Arecibo_Observatory_Aerial_View_small

seti

The project has started in 1999 but until now no sign of (intelligent) life has been found.

You might describe this activity as LISTENING : is there anybody in the universe trying to communicate with us?

What about SHOUTING : is anybody out there? That is the topic of this post. Making our (human) existence known to the universe.

The first attempt to send out a signal to the universe dates back to 1972. The Pioneer 10 space probe was going to explore Jupiter and would leave the solar system after the end of its mission. Carl Sagan , who had been active already in promoting SETI, suggested  that a “plaque” should be attached to the space probe, with information about our human species. The left image gives an artist impression of the Pioneer 10, now traveling in outer space, far away from Earth. It might come close to Aldebaran, a red giant star, in about 2 million years..:-) The right image shows the Pioneer plaque, designed by Sagan and his wife.

1024px-Pioneer_10-11_spacecraft

Pioneer_plaque.svg

For more info about the meaning of the various elements, click on the link above. Here I only want to mention that there was a discussion about the naked humans. Was that acceptable of “porn”? By the way, the male genitals are shown, but the female vagina is missing, so aliens will still be in doubt how we reproduce. Would they be able to interpret the info correctly? Here is a hilarious interpretation: the Real Pioneer Plaque

Five years later the two Voyager space probes 1 and 2 were launched, again to explore the outer solar system. They have been extremely successful and are still operational, after almost 40 years! The Voyager 1 is now 19.6 billion km away from Earth, you can check the actual distance here . It has on board a phonographic(!) record containing information about Earth and about us. A kind of time capsule! The left image shows an artist impression of the Voyager 1 with the location of the golden record clearly visible. The right image shows the cover of the Voyager Golden Record.

voyager

The_Sounds_of_Earth_Record_Cover_-_GPN-2000-001978

Mind you, in 1977 digital coding was not common, no jpeg or mp3 existed yet, it was all analog!. Here is a fascinating Table of Contents of the Golden Record. Please click on this link and be surprised. A welcome message by Jimmy Carter, at that time US president! Greetings in 55 languages. One of them in Dutch (yes!), another one in Indonesian, four Chinese dialects, but no Malay, nor Tamil..:-(  Music, from classical until modern. But this time no picture of naked humans, thanks to a (still) prudish US..:-).

If ever an alien civilization would pick up this time capsule, would they be able to decipher it? Some sources doubt it,  check this funny Gizmodo report

You might compare these first attempts with throwing a bottle in the ocean. Maybe somebody will ever find it. Can we get more active?

Yes, we can. In 1974 the Arecibo telescope, mentioned above, sent out the Arecibo message to the Universe. A sequence of 1679 zero’s and one’s. Why that number? Because it is a semi-prime, product of two large prime numbers 23 and 73. When you order the message, split in a matrix of 73 x 23, you will get this (in black and white!):

320px-Arecibo_message.svg

To “explain” this, the white part represents our decimal system, the green one the  nucleotides  in our DNA, the blue one the double helix. The red human has next to it the human size (in binary) and the human population (also in binary), but probably you understood that already, didn’t you…LOL? Yellow represents our solar system, the third planet is shifted to the left with the human standing on it. Easy, right?

But would you be able to reconstruct the content from this binary sequence?

000000101010100000000000010100000101000000010010001000100010010110010
101010101010101001001000000000000000000000000000000000000011000000000
000000000011010000000000000000000110100000000000000000010101000000000
000000000111110000000000000000000000000000000011000011100011000011000
100000000000001100100001101000110001100001101011111011111011111011111
000000000000000000000000001000000000000000001000000000000000000000000
000010000000000000000011111100000000000001111100000000000000000000000
110000110000111000110001000000010000000001000011010000110001110011010
111110111110111110111110000000000000000000000000010000001100000000010
000000000011000000000000000100000110000000000111111000001100000011111
000000000011000000000000010000000010000000010000010000001100000001000
000011000011000000100000000001100010000110000000000000001100110000000
000000110001000011000000000110000110000001000000010000001000000001000
001000000011000000001000100000000110000000010001000000000100000001000
001000000010000000100000001000000000000110000000001100000000110000000
001000111010110000000000010000000100000000000000100000111110000000000
001000010111010010110110000001001110010011111110111000011100000110111
000000000101000001110110010000001010000011111100100000010100000110000
001000001101100000000000000000000000000000000000111000001000000000000
001110101000101010101010011100000000010101010000000000000000101000000
000000001111100000000000000001111111110000000000001110000000111000000
000110000000000011000000011010000000001011000001100110000000110011000
010001010000010100010000100010010001001000100000000100010100010000000
000001000010000100000000000010000000001000000000000001001010000000000
01111001111101001111000

 

These communication attempts date back quite a long time. Here is a recent one. On 9 October 2008 a high-powered digital radio signal was sent towards the Gliese 581c extrasolar planet: called A message from Earth. Followers of my blog may remember Gliese 581 as the name of a star with more than one habitable planets in orbit. Here is the blog report: New extrasolar planet has been discovered

The distance is about 20 light year, the message will reach the star in early 2029. If “they” reply immediately , we may expect a reply around 2050…:-) Here is the Ukrainian (!) telescope used to send out the message, and a sketch of the Gliese 581 planetary system.

70-м_антенна_П-2500_(РТ-70)

Gliese-581d-habitable-BEST1

Let me end this post with a question:

Is it wise for us to make our presence known to the Universe?

Stephen Hawking is not so sure about it and he is not the only one. Contact with aliens  could be risky.If aliens visit us, the outcome would be much as when Columbus landed in America, which didn’t turn out well for the Native Americans ,” he said. “We only have to look at ourselves to see how intelligent life might develop into something we wouldn’t want to meet.”

A contact with aliens might be very different from Spielberg’s Close Encounters of the Third Kind, my favourite science fiction movie, released in 1977.

Close_Encounters_of_the_Third_Kind_Aliens

About galaxy SDP.81

This astronomy blog needs a fairly long introduction, sorry…:-)

Our Sun is one of the more than 100 billion stars in the Milky Way galaxy. Here is the Milky Way, as seen from Earth. Many of you may never have seen this “milky” band, because you need a clear sky without light pollution. Next to it an artist expression of the Milky Way with the location of our Sun indicated by a red arrow.

milky-way-afpgt

milkywayr

The Milky Way is one of the about 100 billion galaxies in the observable Universe. The Andromeda galaxy (left pic) is a close neighbour at a distance of about 2.5 million light-year.  The picture to the right was taken by the Hubble telescope. This image shows about 10.000 galaxies!

m31big_small

01_January_small

Many of you will have seen (and admired) the images taken by the Hubble telescope. Here is the telescope, it is still orbiting Earth at an altitude of ~ 550 km. Next to it the probably most iconic Hubble image, nicknamed the Pillars of Creation.

HST-SM4_small

pillars of creatrion_cropped

But not many of you will have heard about the Herschel telescope! This space telescope has been operational from 2009 to 2013. Its major objective was to discover how the first galaxies formed and evolved, starting from clouds of gas and dust. These clouds are not yet hot enough to emit visible light, but they still emit (thermal) radiation with wavelengths in the far infrared. It is this far infrared and sub-millimeter radiation that Herschel has recorded. Here is the Herschel telescope and a picture, taken by it. Not as spectacular as the Hubble pictures, right?

image description

Herschel-ATLAS_SDP_display

Actually, each pinprick in this image is a galaxy! Or better, a galaxy “under construction”, still basically a contracting cloud of gas and dust, Hubble would not be able to see them. Most of these galaxies are billions of light years (ly) away, the radiation we receive now, has been sent out when the universe was young.

We are finally coming closer to SDP.81. It is one of the baby galaxies (ID81 in the image below), discovered by Herschel, at a distance of about 11.7 billion ly .  Why is it (and a few more) so bright ?

Herschel-ATLAS_SDP_lenses_small

Here comes the surprising answer: because its radiation has been magnified by a gravitational lens between this galaxy and earth!

A gravitational lens? Yes, Einstein’s General Theory of Relativity predicted that light can be bent by massive objects. Or, formulated more correctly, massive objects will curve the fabric of space-time. His theory was spectacularly confirmed in 1919 during a solar eclipse (and made Einstein instantaneously famous!)  Here is a schematic diagram of this light bending.

4a4a7

In the case of SDP.81 a massive galaxy is located, 3.4 billion ly from Earth, exactly between us and SDP.81. A rare coincidence? Sure, but keep in mind that there are 100 billion galaxies..:-)

A  gravitational lens works differently from a traditional lens where the light bending is strongest at the edge of the lens. Here it is the other way around, bending is stronger near the center. When the alignment is perfect the (magnified) image becomes a ring,  a so-called Einstein Ring. Here are a few examples of Einstein rings, images (in visible light) taken by Hubble. Some are only partial because of misalignment.

hubble_ein_rings

Wouldn’t it be great to find out if the image of SPD.81 is also an Einstein ring? Then we need a much higher resolution then the (already large) 3.5 meter mirror of Herschel could give us.

Alma can help us! ALMA stands for Atacama Large Millimeter/submillimeter Array. It is a collection of 66 radio telescopes  (with 12 and 7 meter antennas), located at 5000 meter altitude in Chili. Here is ALMA

DCIM114GOPRO

Technically it is called an (astronomical) interferometer. To keep it simple: the radio telescopes work together in such a way that they effectively combine to a huge mirror of many hundreds meters or even kilometers diameter. The telescopes can be moved around. The high altitude has been chosen because the climate in the Atacama desert is extremely dry, crucial for observations in the millimeter/submillimeter range. The maximum resolution has been described by the  Alma astronomers as being “about the same as seeing the rim of a basketball hoop atop the Eiffel Tower from the observing deck of the Empire State Building“.

Here is Alma’s result for SDP.81, published a few weeks ago. An almost perfect Einstein ring! Keep in mind that this radiation is invisible, the red color has been added for the dramatic effect. And the visible light of the lensing galaxy is not recorded by ALMA.

ALMA_image_of_the_gravitationally_lensed_galaxy_SDP.81_small.

And here is a combination of three images. The left image is taken by the Hubble space telescope. The lensing galaxy is visible. The middle picture shows the Alma result, in more subdued colours. And the third picture? Montage of the SDP.81 Einstein Ring and the lensed galaxy

The Einstein ring in the middle picture is a “distorted” image of SDP.81. But, assuming a (simple) model for the gravitational lens in between, you could try to reconstruct the “real” image. And that’s what has been done with the third image as result.

An (approximate) image of the SDP.81 galaxy how it was, almost 12 billion year ago, when the Universe was still young. Some structure is visible, the bright parts are regions of dramatic star formation.

Amazing!

Close Encounters

The Close Encounter concept has been introduced by ufologists, people who believe in ufo’s and aliens. You will not be surprised that I don’t, although, to be honest, the Spielberg movies  E.T. and Close Encounters of the Third Kind, belong to my absolute favourites….:-)

Close Encounters

The close encounters in this blog post are different and more prosaic . Not between humans and aliens, but between spacecraft and “celestial bodies”. In the past  fifty years hundreds of close encounters have taken place, with spacecraft flying by, orbiting or even landing on planets, moons, comets and asteroids in  in our solar system. If you are interested in the whole list (314! and counting), surf to NASA’s National Space Science Data Center and select “Planetary Science”.

In this year there will be two memorable and exciting close encounters.

DAWN

Next week ( 6 March), the Dawn spacecraft will enter orbit around the asteroid Ceres. Here is an artist impression of Dawn and its travel to Ceres, starting already in 2007

Dawn

The asteroid belt is located between the orbits of Mars and Jupiter. Ceres is, with its diameter of  950 km, the largest of the asteroids. When it was discovered in 1801, it was considered a planet for some time. As you see, on its way to Ceres, Dawn has first explored Vesta, the second-largest asteroid (diameter 525 km). Here is a composite image of Vesta taken by Dawn. Note the three craters, nicknamed the “snowman” and the “bump” at the south pole, a mountain twice as high as Mount Everest…:-)

Vesta

Dawn left Vesta in September 2012 and is now closing in on Ceres. Here is a picture taken by Dawn ten days ago, on 19 February. Note the two bright spots. The scientists have no clear idea yet what they are, and of course they are getting excited…:-)

Ceres

Ceres is the final destination of Dawn. The coming months it will explore the surface of Ceres  from various distances and finally settle down in a stable orbit (July 2015). You can follow Dawn on the Dawn Blog

NEW HORIZONS

On 19 January 2006 the New Horizons spacecraft was launched from Cape Canaveral. Destination: Pluto, at that time still the ninth planet of our solar system. But not for long, because later that year Pluto was degraded to the status of dwarf planet, together with Ceres. The left picture shows the trajectory of New Horizons, with its actual position on 28 February, the right picture gives an artist impression of the spacecraft closing in on Pluto and its moon Charon.

New Horizons trajectory

New Horizons and Pluto

After passing Jupiter in 2007, the spacecraft has gone into hibernation for considerable times, to save energy. Every now and then waking up to let Earth know that it was still alive…:-). Last year in December, it became fully awake again.

As you see, Pluto is an outsider, with its very elliptical orbit. We know consider it a member of the Kuiper Belt. The spacecraft will fly by on 14 July this year and come as close as ~ 10.000 km! How will Pluto look like? Here is an artist impression of Pluto’s surface, its moon Charon and the Sun. Yes, that is our Sun, not much more than a bright star. Communication with New Horizons takes more than 4 hours, one way.

Pluto

If the spacecraft keeps functioning, we will know a lot more about Pluto after the fly by. Exciting!

New Horizons will not go into orbit, just fly by. With the little fuel left, it will try to visit a few more members of the Kuiper Belt, and then leave our solar system, like the two Voyagers before. But that is a topic for another post.

ROSETTA

One more memorable event in 2015. I have reported a few times already about Rosetta, now in orbit around the comet 67P. This comet will reach its perihelion (closest to the Sun) in August this year. Already part of the comet is evaporating (forming the famous “comet tail”). Rosetta is still exploring the comet from various distances. The left picture, taken from far, shows the evaporation. The right picture is a close-up from the surface, taken from a distance of 8.9 km only!

67P

close up

The location of the Philae lander is still not accurately known. The scientists are hoping that soon this lander will get enough sunlight (it is probably in the shade of a rock wall) and will wake up again. Let’s keep our fingers crossed..:-)

 

Meet your great-(~10 million times)-grandmother

In my blog The Tree of Life, published a few months ago, I wrote about the Last Common Ancestor (LCA) of all placental mammals, that it was a shrew-like animal, living about 65 million year ago. Terrestrial, with insects and fruits as food.

Our maternal ancestor

Yesterday Yale University has published an interesting update. Our ancestor most probably was not terrestrial, but lived in trees. More a squirrel than a shrew. This conclusion was drawn, based on a study of fossil ankle bones of Purgatorius as our LCA was named.

purgatorius