Wait a second!

Tomorrow, 31 December 2016, just before midnight, an extra second will be added to the Universal Coordinated Time  (UTC)! It is called a leap second.


Probably everybody will be familiar with the concept of a leap day . A year in the international  calendar has 365 days, but the solar year is a bit longer, 365.25 days. To keep this calendar synchronised with the solar year,  every four years an extra day (29 February) is added to the calendar, a leap day. 2016 was a leap year, the next one will be 2020.

The Chinese calendar is based on the motion of the Moon, orbiting the Earth with a period of 29.53 days. A (lunar) year is 12 months = 12 × 29.53 = 354.36 days, about 11 days shorter than the solar year. To keep this calendar synchronised with te solar year, every two/three years an extra month is added, a leap month. Next year will be a leap year in the Chinese calendar, it will have 13 months with one of the months duplicated. Not always the same month, this time the 6th month. More detailed information about calendars can be found on my website

For those not familiar with UTC, it is the primary time standard by which the world regulates clocks and time. It is basically the solar time at 0° longitude, with the solar day as fundamental unit. The 0° meridian passes through Greenwich, therefore UTC is sometimes called Greenwich Mean Time (GMT). The world has been divided into 24 time zones, they are defined as UTC plus or minus a number of hours. For example Malaysian time is UTC + 8.

So, the UTC is based on the (solar) day and a day is 24 x 60 x 60 = 86400 seconds, right? Why do we need to add a leap second? The answer is simple, but may surprise you.

A (solar) day is not exactly 86400 seconds!

Here is a graph of the “extra” length of day over the last few decades. Click to enlarge and see more details


It is only a few milliseconds every day, but it accumulates! Therefore it has been decided, in 1972, to add an extra second to UTC, when this accumulated deviation gets more than 0.9 second. The red graph shows when leap seconds were inserted.  As you see, the deviation from 85440 seconds is quite irregular and actually not predictable. That’s why the leap seconds are announced only 6 months in advance.

Why are the deviations always positive? That has an interesting, physical, reason. It is because of the moon! The moon is responsible for the tides, causing friction! This friction slows down the rotation of the Earth! It is a small but real effect, the solar day increases about 1.4–1.7 milliseconds per century. There is geological evidence that about 500 million year ago, the length of the day was shorter, ~ 22 hours.

These tidal forces and eventually tidal locking might be an interesting. topic for a separate blog.

A few remarks

  1. The leap second will be added to UTC, 31 December at midnight. 23:59.59 will not be followed by 00.00.00 but first by 23.59.60
  2. In Malaysia (UTC + 8) the leap second will be added on 1 January.  07:59:59 should not be followed by 08:00:00 but first by 07:59:60.
  3. Computer guys are not happy with an insertion of an extra second. It may cause computer failure. The Google engineers will just slow down the system clock slightly, from 10 hours before, until 10 hours after midnight, resulting in 1 second extra…:-)  Technical details here
  4. Time reckoning is a complicated topic. I have simplified it here…:-)

Jeram Janggut

Because I am the owner and webmaster of the Waterfalls of Malaysia website, my friends call me sometimes the Godfather of the Waterfalls, so it makes sense that I also have Waterfall Godsons..:-). Three of them at the moment, Siang Hui, Teoh and Nick. Siang Hui knows a lot of virtually unknown waterfalls and when Teoh a few weeks ago proposed to make a waterfall trip, SH suggested Jeram Janggut in Negeri Sembilan. An easy hike, he promised.

As it was rainy season, we decided to start early. At 7 am Teoh picked Aric and me up from our home and we drove to Sg Long where we met Siang Hui and Nick. After breakfast we continued in Teoh’s Hilux.

Start from Sg Long

It was quite a long drive to the trail head, first to Seremban, from there to Kuala Pilah. About 7 km before Kuala Pilah a minor road leads far (~20 km) into the mountains. If you have a hard-core 4WD you can almost drive to the fall. We started hiking at 10 am, walking the last few km. Here is my gang, from left to right Siang Hui, Nick, Teoh and Aric.

My gang

The route took us through a plantation, easy going, although often muddy and sometimes confusing because of several splits and junctions.

We wanted to keep close to the river, so we took this small trail, which ended at an abandoned Orang Asli house near the stream. Maybe we could have river trekked to the fall from there, but we decided to go back and follow the main road

Wrong path

O.A. hut

That meant that we had to cross a ridge, first going up steeply, nice views of the surroundings, then going down again. A signboard, “Not allowed to use poison or explosives for fishing”, meant that we had reached our goal.

The Jeram Janggut waterfall is not spectacular, but nice, with a large pool.

Jeram Janggut

We frolicked around, had coffee and of course took pictures.


Many pictures….:-)


Here is a short video of the fall.

We didn’t stay too long, as clouds were coming in, but before we left Aric used his iPhone on a tripod to take an “official” picture of our gang. I am very pleased with the result, we all look good and happy.

The gang

There is a lower tier of Jeram Janggut, quite nearby, but you have to scramble down a steep slope. We just had a look from above.

Lower Tier

Here is a video of this lower tier.

Going back to the trail head took us about one hour. Watching the butterflies having their lunch, we also got hungry…:-)



We where just in time, when we reached our car, it started raining! Just where we reached the main road, we found a Malay stall, serving Assam Laksa, nothing special according to Aric (our assam laksa expert!) but delicious Kelapa Cendol.

It was a nice rewarding trip. The fall can be reached by (hard core) 4WD, we were lucky to be alone there. Here is a GE screenshot of the region. There are several relatively unknown waterfalls in this section of the Titiwangsa range. Jeram Tengkek is on the WoM website, the others not (yet), for various reasons.

Note the red marker. In 1945, just before the Japanese surrender in World War II, an allied Liberator plane crashed here and was only found by locals in 1961. The remains of the plane are still there and it is possible to hike to the crash site. Something for another trip


Let me finish this waterfall post with a screenshot of my Waterfalls of Malaysia site, that shows where the visitors of my website come from. I started checking 5 years ago. In those 5 years almost 1.5 million visitors from 190 countries have been visiting the site. Not a bad result…:-)

visitors WoM

Neighbour, here we come!

In a recent blog, Our nearest neighbour? , I reported about the discovery of the planet Proxima b, orbiting around a star, “only” 4.22 lightyear away from Earth. In several media it was suggested that within a few decades a spaceship could be launched to reach this planet. A spaceship is science-fiction, but there exists an ambitious plan to send a swarm of space-chips to Proxima b within a few decades. I promised to write a separate blog about this Breakthrough Starshot  Here it is.

In 1865 the French novelist Jules Verne wrote De la Terre à la Lune (From the Earth to the Moon), in which he describes how three adventurers travel to the moon in a projectile, shot from the earth by a large cannon. I have read it spellbound when I was a teenager. You can read it online here , it is fascinating (and hilarious too).

The illustrations are beautiful. Here  are some. From left to right the three adventurers climbing into the projectile, the comfortable interior and the firing of the canon.
verne1 verne2 verne3

Why this introduction? We know now that this method is not used in our space age. We don’t shoot our spacecraft to the moon or other planets, we use rocket propulsion.  The  Voyager 1 (825 kg) was launched by a Titan-Centaur rocket (600.000 kg). The images show the launch, the Voyager spacecraft and a structure diagram of the rocket. The Centaur is mounted on top of the Titan. A huge amount of fuel is needed to launch a “tiny” payload!

Voyager & Titan


After completing its mission, the Voyager is now leaving our Solar System with a speed of more than 60.000 km/h That is fast but it would still take about 75.000 year to reach Proxima b, if it was going in that direction (which is not the case).

So we can forget about  space travel to the stars, using rocket propulsion, at least in the foreseeable future. Is there another option, more in the style of Jules Verne?

Actually there may be one…:-)

One year ago Travis Brashears, a graduate student at the University of Santa Barbara in California, and his supervisor, Philip Lubin, professor of astrophysics and cosmology at the same university, published a paper Directed Energy Interstellar Propulsion of WaferSats in which powerful lasers “shoot” miniature (~ 1 gram only!) electronic chips away from earth in the direction of a nearby star, with a speed approaching the speed of light! Here are the (main) writers , Brashears left and Lubin right.


Does this sound as science fiction? For me it does. But apparently not for these guys.

Sure, light exerts pressure, there are several projects going on, using sunlight propelling a solar sail , a bit similar to the sail of a sailing boat being blown by the wind. One successful project is IKAROS, a solar sail of 196 m (!) , launched in 2010 by Japan. Here an artist impression of the sail, with Venus, its destination. The sail is so big. because the thrust of the sunlight is only small.


Next year March the LightSail 2 will be launched. To the left the actual spacecraft, a so-called cubesat. To the right an artist impression of the LightSail in space, with a deployed sail. Notice how small the cubesat is compared to the sail!



These projects are using sunlight. The project of Brashears and Lubin is futuristiic.

  1. A ground-based laser will be used as a “shotgun”  Estimated power needed 100 GW. That is a lot! The Three Gorges Dam in China, the largest power plant in the world, generates 22.5 GW.
  2. The spacecraft will be a chip with a mass of about 1 gram, with a light sail of ~  1 m2   . The plan is to prepare about 1000 of these miniature “spacechips” and launch them simultaneously in a mothership, orbiting the earth. From there the starchips will be shot, one after another on a daily basis, during 3 year.
  3. The laser will give a spacechip in about 10 minutes a speed of 20% of the speed of light. That is fast , 60.000 km/s
  4. The spacechips will reach Proxima b in about 20 year. Hopefully at least a few of them will have survived the journey.
  5. They will send back pictures to earth.
  6. Estimated cost of the project US$ 5-10 billion.
  7. Proposed launch date about 20-30 years from now.

Here is an artist impression of the launch. Mind you, the spacechip is the tiny dot in the center of the light sail!


Futuristic indeed. The time span of 20-30 year is because much of the technology still has to be developed. Designing a spacecraft on a centimeter-size, gram-scale chip, developing a light sail with a thickness of 1 micron or less, building a 100 GW laser and many more challenges.

Here another artist impression. The plan is to build a so-called “phased”  array of smaller lasers, with a combined power of 100 GW. If you use 100 kW lasers ( at the moment the maximum power available), you need a staggering 1 million of them.

Laser array

I am skeptic, as usual…:-) But not everybody is. Yuri Milner, for example is optimistic.  This Russian/American tech entrepreneur and multi-billionaire,  started as a physicist and is very interested in the big question “Are we alone in the universe“. In July 2015 he announced, together with the British physicist Stephen Hawking, the Breakthrough Initiatives , a program to search for extraterrestrial intelligence. At that time the program consisted of two parts.

  1. Breakthrough Listen.  Basically a large-scale version of the SETI project. Funded by Milner with US$100 million.
  2. Breakthrough Message. A prize pool of 1 US$ 1 million for the best (digital) messages that could be sent out into deep space. No concrete plan to actually send these messages, because for example Hawking thinks it might not be advisable to do that. See my blog Anybody Out There?

In April 2016, part 3,  Breakthrough Starshot, was announced by Milner and Hawking. Milner and Mark Zuckerberg (FaceBook) will contribute another US$ 100 million to explore the technological feasibility of the program outlined above.

Milner, Hawking and Dyson

From left to right Yuri Milner (holding a protoype of a spacechip in his hand), Stephen Hawking and “eminence grise” Freeman Dyson, a physicist and cosmologist, now 93 year old. If you are interested in really futuristic ideas, have a look at his Dyson Sphere 🙂

Below is an animation of the process. A few comments may be useful.

  1. There are 135 lasers in the array. You need at least 1 million.
  2. The spacechips are launched simultaneously in a container, but released and shot one after another.
  3. When they reach Proxima b after ~ 20 years, they will pass the planet at full speed (60.000 km/s). So fast that the camera on board can only take a few pictures. Also data will be collected about magnetic fields etc.
  4. These data will be sent back to earth, using miniature lasers on the spacechip, focused with the help of the light-sail.
  5.  About 4.22 year later, the ground-based laser array will receive these data. Hopefully…:-)

I have been working about two weeks on this blog, reading and collecting as much information as I could find. To be honest, I became more and more skeptic.

A few days ago Scientific American has published a very informative article about the Starshot Program: Inside the Breakthrough Starshot Mission to Alpha Centauri. Many scientists were asked for their opinion about the project. There is respect for the technological challenge, but scepsis about the scientific value.

Jean Tinguely

Jean Tinguely (1925-1991) was a Swiss artist, best known as a creator of “machine sculptures” .  Made of scrap metal and junk, with an electric motor which keeps part of them in motion, these useless, playful and sometimes noisy machines have fascinated me from the first time I saw them, in the Municipal Museum of Amsterdam. That was in 1973, more than 40 years ago…:-).

This year, 25 year after Tinguely’s death, the Stedelijk, as it is commonly nicknamed, has an impressive retrospective of his work, named MACHINE SPECTACLE with over a hundred machine sculptures, many of them in working order. The exhibition is open until 5 March 2017 and definitely worth a visit.

Here is one of his works that actually belongs to the museum collection. It is called Meta II, created in 1971, and I have seen it in 1973. It makes an awful lot of noise…:-)


Not during my recent visit. Many of Tinguely’s creations are actually quite fragile, the museum staff has been busy many months to get some of them them working again. Therefore it was decided not to keep them running permanently. Only on specific times, they work for a short period and only when you push a button.


Here you see a few of his machines. Some of them have a timer, so you can see when you have to push the button, many have not, you just have to try. Not really a good design.

The result is that the (many) visitors walk around the many rooms with (inactive) exhibits, until they hear a noise. Then they hurry to where the sound came from, because it lasts only a short time.

Quite funny, in a way.



Here are a few working ones. Doesn’t it make you feel happy when you see those useless contraptions in action? But, as you will notice, only for a very limited time.

A few more, not in action. Click to enlarge and see details. Notice the paper tape in two of the pictures. Those machines create “art” themselves when they are operating! Tinguely’s Metamatics (Wikipedia) has more info about this

And here is Gismo, created in 1960, also belonging to the collection of the Stedelijk. It is so fragile that even during this retrospective, it will be operated (by one of the museum staff)  on a few specific days only. Check the website if you are interested, scroll down to “When do the machines move?”


This one, looking more serious, has been on loan from another collection, the Centre Pompidou in Paris. Created in 1967.


But how serious is it? The title  is:  Requiem pour une feuille morte. Not a requiem for a dead  girl (fille) but for a dead leaf (feuille)  Here is this requiem in action.

Tinguely belonged to the Parisian avantgarde in the mid-twentieth century and was a member of the Nouveau Réalisme group, founded in 1960 and dissolved in 1970. Many well-known artists in this group, like Yves Klein, Spoerri, Niki de Saint Phalle and Christo.

Actually Tinguely and de Saint Phalle were married and have been working together often. In this exhibition one characteristic work of her is exhibited.Niki de Saint Phalle

And here is a co-production of the two artists, named  Crocrodome (1977)


A very interesting one is this model for  a huge project in a forest near Paris, Le Cyclop. Started in 1969. Many artists have been contributing to it, it was finished by de Saint Phalle in 1994, after the death of her husband. I had never heard about it, really like to visit it when I am back in Europe.

Model for the cyclope

Very impressive is also the Mengele-Totentanz, a late work (1986) with an interesting background story. A farm, near Tinguely’s studio was struck by lightning and burned down. Several cattle could not escape and died. Tinguely immediately started to collect scrap metal from the remains and created this huge work of art. Part of the installation is a harvester made by a firm named Mengele (the firm still exists). But Mengele is of course also the name of the notorious German concentration camp physician. It gives this monumental work a double meaning.

Mengele Totentanz

The Totentanz belongs to the collection of the Tinguely museum in Basel and has never before been exhibited in the Netherlands. Must have been a big job to disassemble it in Basel, transport it and then assemble it again in the Stedelijk…:-)

Here is a video

Really a very interesting exhibition

Strata revisited

It was in 2005 that I read a post in one of the Malsingmaps forums about an unknown waterfall near Tanjung Malim. GPS-tracks and the coordinates of this Strata waterfall were given.

Here is the track (in red) and the waterfall, superimposed on a topo map of the region. Click on the map to enlarge it.


Notice that the track is broken, it is not very accurate. Starting point is the Diamond Creek resort, which did not yet exist when the topo map was printed. I have indicated (in white) the location of the roads in this (rundown) resort. I have also marked (in blue) two rivers, to guide the eye. The Strata fall is located in the Sg Sekiah, the Gerehang river has also a waterfall, which I hope to revisit soon

Of course I was interested to visit this fall, so in the following months I went several times to Diamond Creek, and finally found the waterfall. I have written two reports about these trips. The first report, The Strata Fall, Prologue & First Acts , describes the first attempts where we followed a trail high up the left bank of the river and found the Upper Strata Fall. In the second report, Strata Fall, the Grand Finale, we decided to river trek and finally found the main Strata fall.

The map shows the two routes, the yellow one leading to the upper fall, the brown one following the river to the main fall. The reason that the original (red) track is so scanty, especially in the last part, is that the river flows in a deep ravine where GPS reception is not easy. Even with my Garmin GPSMap 64s, there was a lot of scatter, which I have smoothed out.


That was more than ten year ago! Recently one of my friends wanted to visit this fall and I gave them my GPS-data. They did a recce, but did not reach the main fall.

My friend Edwin had told me that he had visited Strata beginning of this year, crossing the river to the right bank and following a rather clear trail to the fall without river trekking. That sounded interesting! He was willing to go again and be our guide. Here is our group.  From left to right  Paul, Fahmi, Edwin, Jan, Chin and Tan. Picture taken by Aric

Our group

We started walking from the Diamond Creek resort, with a 4WD we could have gone much further in. Sometimes it was a bit confusing which road to choose..:-)



Passing through the plantation and entering the forest, we came closer to the stream and the point where we had to cross the river. The sign Hutan Simpan Kekal says that this is a Permanent Forest Reserve. So we were shocked when we saw that less than 100 meter further, a new logging bridge had been constructed over de river.



This was all still unspoiled forest when Edwin came here earlier this year. Shameful. And a problem for us. Of course the building of the logging roads had also destroyed the existing trails. So how to proceed? With some scrambling we managed to climb up to the logging road (marked with a red X).


We decided to cross the stream on this logging bridge and then try to find the trail on the other side. We chose what looked like a kind of trail


But it was not a real trail and soon it petered out in a chaos of tree trunks and branches. Pictures taken by Chin, our selfie-man. Edwin suggested to do a recce, because he was confident that it should not be far to the old trail.



We waited for him (picture by Aric)


When he came back after about ten minutes, he said that he had seen the trail down the slope, to reach it might not be easy, but should be possible. So we continued and indeed, after scrambling not more than 100 meter, we reached the trail. Kudos for Edwin!



The trail was remarkably clear, not overgrown, apparently also used by other hikers.It was only about 500 meter to the fall, which took us less than half an hour. And a beautiful waterfall it is!

Strata fall

We arrived at the fall at 11am and stayed one hour, because we were expecting rain in the afternoon. Enough time to enjoy the view, and take a bath. And pictures of course, or selfies…:-)

Of course I also wanted to refresh myself. Because I sweat easily, which attracts wasps and bees, I often take a plunge with all my clothes on and often also my shoes. As you can see in the left gallery picture, the pool is not deep. Except to the right of the fall and that was where I aiming at. When I touched the rocks, I could feel already that there was a strong current to the left. I tried to swim back but did not make much progress. Edwin noticed that and rescued me!  I was not (yet) panicking, but appreciated his help.

On our way back, we found, as we actually expected, that there was a better way to cross the river than using the logging bridge. We found even a marker, proof that more people come here.



Here is the map of our hike. Click to enlarge. Part of the logging road is indicated in brown. The scrambling part is the dashed-green line. The river crossing and the location of the marker are given.


Here is a short video of the Strata Fall

It was an interesting and rewarding trip. I have described the hike in detail, it might help others to find the way. Sad that they have started clearing the forest. Here is one more picture of the damage already done