Moon Formation: Zinc Makes Collision Theory More Plausible

Bash the Earth up and get a moon- that’s the theory that scientists have been looking at for a long time. However, the signs of violence are very subtle and very difficult to detect. It turns out that this cataclysmic event leaves behind a trail of only slight imbalance in the different varieties of zinc. Yes, boring – completely boring – to a layman, but to a scientist, it’s like adrenaline.

The Big Smashup?

Written down in Zinc

Planetary expert Frederic Moynier and his group at Washington University in St. Louis have claimed that they have discovered this tiny imbalance of zinc in the rocks of the Earth and that of the Moon. The theory goes like this: in the catastrophic event, under very hot conditions, heavier zinc atoms sunk in and condensed, while lighter ones escaped before condensation. These two isotopes (different atoms of the same element which differ only by their weights and not by their chemical properties) of zinc on the Moon will, thus, bear a ratio of their abundance different from what it is on Earth. In simpler language, say, the heavier zinc atoms outnumber the lighter atoms by a ratio 5:1 on Earth. On the moon, this ratio will be slightly (and not wildly) different – it can be say 6:1. Given that the other elemental abundances match very well, it is this tell-tale difference between the zinc ratios that should give us hints of its fiery origin.

Volatile situation

The moon rocks are chemically similar to those on Earth, except that the volatile elements are gone! This would be expected if a large body slammed into the Earth releasing a huge chunk of material that eventually formed the moon. Most of the Earth would retain whatever elements it had, but the Moon wouldn’t.

This loss of volatiles will also be accompanied by a process due to which heavy zinc atoms would outnumber the lighter zinc atoms! And this is precisely what the team found by analyzing the moon rocks.

In order to make sure that this depletion of the lighter zinc species is not a local aberration, i.e. located around only one point on the Moon’s surface, the team analysed rocks from different moon missions. These missions had picked up rocks from all over the moon and all the samples recorded the same heavy to light zinc ratio. This observation cannot be explained by any other theory and gives credence to the collision theory.

Sometimes, the smallest clues are the way to solve a great mystery. The jury is still undecided on this, however.

The technical study appears here:
http://www.nature.com/nature/journal/v490/n7420/full/nature11507.html

Shopping for Diamonds—in Space

Astrophysicists are hypothesizing that a previously discovered planet could have a diamond interior.

This planet, called 55 Cancri e, is an exoplanet (a planet outside the solar system) that orbits a star called 55 Cancri. Its was the one of the first ‘Super-earths’ to be discovered—its mass is greater than that of earth (around 7.8 times), yet much smaller than the masses of Uranus and Neptune. Estimates of its interior composition and atmosphere had already been made from previous studies observing its transits across the star (similar to the much talked-about Venus transit earlier this year). It was estimated that this planet had a core of iron and silicates, and an envelope of supercritical water (i.e., water in a blurred state between liquid and gas).

However, these estimates were based on the assumption that the planet had an oxygen-rich interior, similar to earth. This assumption is now being challenged in a new model proposed by researchers at Yale University. The star around which the planet orbits itself has a carbon-rich interior, and 55 Cancri e is the closest planet to the star. This led to a new model that the planet could have an interior of carbon instead of oxygen, which could also lead to the observed properties of the planet.

An illustration of the planet 55 Cancri e’s interior. A molten iron core at its center, an outer layer of graphite, and an interior of diamond. [Image Credit: space.com and Haven Giguerre]

However, based on the known temperature and pressure of 55 Cancri e, any carbon in its interior would have to exist in the form of diamond. “This is the first glimpse of a rocky world with a fundamentally different chemistry from Earth. The surface of this planet is likely covered in graphite and diamond rather than water and granite,” said Nikku Madhusudhan, who was the first author on this paper.

If this proves to be true, the phrase ‘like a diamond in the sky’, may turn out to be more than a simile. You can read about this research here and here.

Hubble Space Telescope Discovers Pluto’s Fifth Moon

Tiny Pluto has a lot of followers. Being relegated to being a ‘dwarf planet’ from being a ‘planet’ has apparently not hurt Pluto’s chances of capturing a moon. It already has four moons, all of them tiny. Now, a fifth one has been discovered by the Hubble Space Telescope.

The fifth moon. Pluto is somewhere in the darkened area.
Image courtesy: NASA, Hubble Space Telescope, ESA and M. Showalter from SETI.

New Moon!

We covered the news of the discovery of the fourth moon of Pluto here and it was called P4. This new one has been provisionally christened S/2012(134340)1, but it already has gained the title ‘P5′. The other moons of Pluto are Charon (biggest), Nix and Hydra, apart from P4.

The announcement of the discovery came through Twitter when principal investigator in NASA’s New Horizons spacecraft Alan Stern said:

Just announced: Pluto has some company – We’ve discovered a 5th moon using the Hubble Space Telescope.

Oh, and the New Horizons spacecraft project plans to fly by Pluto in a bid to discover new horizons and study the dwarf planet. The launch is scheduled in 2015.

Difficult to see

Pluto and its moons are notoriously difficult to see. They tend to be blips of light, in the midst of a background made up of blips of light. The only difference is that the moons of Pluto go around Pluto, rather than the Sun, which the blips of light in the background do. The moons are quite small. Charon is the biggest, measuring about 1000 km across. The scale falls sharply with Nix and Hydra measuring about 80 km or lesser. P4 is about 30 km across.

It turns out that P5 is even smaller. It’s about 20 km across, but at places it measures less than 10 km, indicating that it is highly irregular. It was Hubble’s Wide Field Camera 3 which caught the 5th moon.

Many believe that Pluto might ‘capture’ planetary debris from their irregular orbits around the Sun and make them its moons.

Was Life On Mars Discovered 30 Years Ago?

Simply put, there is life on Mars – or at least that’s the most plausible explanation that NASA scientists can put forward in order to explain certain observations in the lab. A robotic mission launched thirty years ago, the Viking 1 and Viking 2, brought soil samples back to Earth and these have been thoroughly tested for the presence of Martian life, and the tests have been encouraging.

Life Hiding Somewhere?: Photo returned by the Viking Spacecraft (Photo Courtesy: GSFC, NASA)

One of the packages brought back by the Viking spacecraft was collected by the Labeled Release (LR) apparatus. This sample is particularly interesting.

The ticks of life

Soil microbes metabolize and release carbon dioxide, using up minerals in the soil. The carbon in the carbon dioxide contains one radioactive atom in a million million atoms, but since there are lots of carbon atoms around, there is a lot of radioactive carbon as well. And this shows up in any instrument that measures radioactivity, like a Geiger Counter. So the idea is that if a soil sample emits more than its share of radioactive rays, the chances are very high indeed that there are microbes inside, that are churning out carbon dioxide gas, which can escape and be detected. The detector will produce more counts than normal.

They found exactly that! A control sample was put in to confirm that this is indeed due to some source of microbe inside the soil sample. This sample was baked at a high temperature to kill any microbe that might be present. When the two samples were checked for radiation, the unbaked LR sample clocked around 10,000 counts per minute, while the background was only about 100.

However, this is not true of the other two experiments on the Viking spacecraft. This non-confirmation led to the dismissal of the probability of life.

The diurnal cycle of life

Life on any planet, especially if local, adjusts its living patterns – sleeping, hunting etc. – according to the clock on that planet. Lifeforms on Earth have a 24 hour clock schedule, but on Mars the day is 24.7 hours long, and that will be the so-called ‘circadian rhythm’.

The funny thing is that the radiation emitted by the LR apparatus sample also shows this daily cycle. The radiation goes down, indicating a period of inactivity, then goes up again. The oscillation is periodic with the exact period of 24.66 hours.

Joseph Miller, a neurobiologist at University of Southern California, and a member of the study says:

That is basically a circadian rhythm, and we think circadian rhythms are a good signal for life.

No one has yet cultured a Martian microbe. The next spacecraft explorer – Curiosity – which is scheduled to land on Mars in a few days will shed much more light on this very critical issue.

We may not only have company in the Universe, it might even be just next door.
Want more info? Visit this: http://www.ijass.org

Mysterious Eruptions on Venus A Result Of Massive Solar Activity

Strange things are afoot on Venus and we’ve got just a hint as to what they are. Gigantic explosions have been seen on the surface of Venus, possibly triggered by the intense Solar winds, which peaked yesterday. The spectacular explosions occur just above the surface of the planet, since Venus lacks a proper magnetosphere.

How the magnetosphere of a planet shields it from a solar wind. Venus doesn't have a strong enough magnetic field.

Scientists call these Hot Flow Anomalies (HFA’s) and these are common on Saturn. They have also been seen on Mars, but this is the first time such gigantic explosions are afoot on Venus.

An Explanation

Here’s a quick explanation as to why these HFA’s actually happen. The Sun sends out millions of charged particles travelling at very high speeds towards the planet. There are often discontinuities in the solar wind, and this is recorded as a sharp change in the magnetic field of the solar winds.

HFA's on Venus. The charged particles get swept up by this moving front of weak magnetic field. (Image Courtesy: GSFC/Collinson paper)

If these areas lie parallel to the direction of wind flow, the wind can remain in contact with the contour along which the solar wind slows down and changes direction, called the bow shock (marked). If the propagation of the discontinuity is slow enough, it sweeps up enough charged particles. These charged particles form plasma, which sends shockwaves resulting in these gigantic eruptions.

Huge Energy reservoirs

This process happens on Earth too, but the strong magnetic field of the Earth prevents the process from occurring too close to the surface. These processes release a lot of energy. About the HFAs on Venus, David Sibeck, a planetary climate scientist at NASA’s Goddard Space Flight Center says:

Hot flow anomalies release so much energy that the solar wind is deflected, and can even move back toward the sun. That’s a lot of energy when you consider that the solar wind is supersonic — traveling faster than the speed of sound — and the HFA is strong enough to make it turn around.

The study regarding this phenomenon made by Glyn Collinson and David Sibeck, both from GSFC, appeared in Journal of Geophysica; Research.

NASA’s Cassini Spacecraft Detects Oxygen Gas On Saturn’s Moon

It’s not quite breathable, but Saturn’s moon Dione still has a bit of molecular oxygen within its very thin atmosphere. The oxygen atoms are very sparse, only about one molecule of oxygen per 11cubic centimeters (cc) of space. The fact was reported by NASA’s Cassini Spacecraft.

An artist's impression of the Cassini spacecraft flying past Saturn.

But how did it get there?

The interesting bit about the oxygen is how it comes to be! The oxygen is not made by biological organisms, unlike here on Earth, but by physical processes like dissociation of molecules in the atmosphere due to the bombardment by highly energetic photons. They can also come from geological activity. How the tiny Dione holds on to this thin layer of gases is, however, not understood. Saturn’s biggest moon Titan, possibly the biggest in the Solar System, has a thick atmosphere, but then it’s much bigger than Dione. Dione’s atmospheric problem compounds the problem astronomers have of explaining the atmosphere around Rhea, another small satellite of Saturn.

Not that big a surprise

The detection of molecular oxygen was done using ion and neutral mass spectrometers. Earlier, Hubble had picked up the signature of ozone, so molecular oxygen was always on the cards, since ozone is just the oxygen molecule with one more oxygen atom.

It is not clear whether there are rarer gases in Dione’s atmosphere and, if present, what their composition is.

The conclusion comes from analysis of the data taken on the Cassini flyby on Dec 12, 2011.

Enjoy Mars As Seen Through 20,000 High-Resolution Images And Even In 3D!

You may have known Mars, but you’ve never seen it like this! It’s really a scientific tool, but the non-Mars specialists are free to have some fun with it! The Hi-resolution Imaging Science Experiment (HiRISE). It is an awesomely cool science project involving imaging every square inch of Mars, with a resolution of 25 cm per pixel! The camera is built by the University of Arizona and mounted aboard the Mars Reconnaissance Orbiter (MRO). Over the last five and half years, it has returned over 20,620 images till date.  We give you the link below.

http://hirise.lpl.arizona.edu/katalogos.php
Dunes on Mars! No that's not shimmering water.

Addictive Mars!

Make sure you have time when you start browsing through these! It’s extremely addictive and I found myself trying to look at the dunes, then the craters, then the frosted plains, then the translucent ice on domes, then… The list is virtually endless. Go to any of the images and you’ll get numerous download options. Don’t try JP2 formats – it’s for people who want to work with the images and thus they are extremely big (a photo can measure 300 MB in size!). Try the jpeg format, which provides a compressed form of the image. RGB worked best for me. There is a ‘Science Theme’, which links it under a particular tab. Click that and you’ll be provided information on that particular theme, which you’re welcome to either relish or gobble up. You might even notice the ‘stereo pair’ reference, and I’ll explain what they are in a moment.

Downloads and a whole new dimension!

You can download a chunk of the most high resolution images by clicking ‘Updates’ right at the top of the screen. On the right, you should see download options in various resolutions. A click is all you need to take possession of masterpieces!

If you unintentionally click on the ‘Anaglyphs’ tag at the top of the screen, you’ve just discovered something awesome! You’ll see two images, which form ‘stereo pairs’. Combined and with the help of a 3D glass, you can see the images in 3D!! Yes, you read it right – the Martian topography in 3D in the comfort of your own room!

An example of dunes on Mars, which will appear in 3D!

Just one word of advice while using this database: make sure you have fun! Afterall, it’s Mars!

Inferred: 160 Billion Alien Worlds Out There!

No, we haven’t found life outside Earth as yet, but we have definitely improved our prospects. A growing number of telescopes has fuelled a burgeoning number of exoplanet discoveries, led primarily by the Kepler Space Telescope, which has detected 2330 long-period planets (planets having a period of more than a few days) till date. It has performed really well as compared to ground based telescopes, but there are plans to either upgrade it or replace it with a better model. According to Kepler, the count in the Milky Way now turns out to be 1.6 planets per star, and there being 100 billion stars, the count is 160 billion planets just within our galaxy!

An exoplanet (artist's impression). There are 160 billion of them, at least!

Kepler Space Telescope

Kepler works using a very simple principle. It monitors the light coming from certain stars over a period of a number of months. The data is then sent to ground based command centers, which analyse the data and look for the presence of any periodic dimming and brightening events. Any such periodic changes in the brightness of a star suggests that there is another body circling it, which periodically eclipses the star just a bit during its transit. This method also helps the telescope pick up periodic wobbles of the parent star. Observing the wiggles this causes in the spectral lines of the star, scientists can infer not only the presence of an alien planet, but also pinpoint its mass and orbital period.

Earth-like objects

Very recent observations by Kepler show a marked rise in the number of Earth-like rocky planets being discovered. These might not be of the same size of the Earth, or they might not orbit their stars at the optimal ‘Goldilocks’ distance, but they are not gas giants. This is important, since gas giants are not presumed to hold liquid water or harbor any kind of life form.

The study leading to this estimate of the number of exoplanets was led by Arnaud Cassan from the Paris Institute of Astrophysics and their work appeared in the January 12th issue of Nature.

Contact  may not have been such a far-fetched movie after all!

Kepler Receives First Images; Looks To Be From An Alien Civilization, But Isn’t

The 100-m Green Bank Telescope in Virginia has just picked up a strange radio signal, originating from KOI 817 (with KOI standing for Kepler Object of Interest) that looks as if an alien civilization is transmitting to us. SETI is excited as this is the type of radio signal it would expect from an alien civilization.

The signal that Green Bank picked up.

Not from an alien world

However, before the excitement can get too wild, SETI says that this signal is definitely terrestrial, rather than extraterrestrial. The signals have “terrestrial radio frequency interference” or RFI. Right now, the signals are a great source for SETI astronomers to study radio-frequencies, should they encounter a radio-emitting alien civilization.

The radio signals are narrow in frequency range (photo above), much narrower than anything that would be produced by an astrophysical radio source. The frequency of the signals is also perfect! Even the Doppler shift is just right, with the frequency decreasing at the precise rate expected from the relative motion of the transmitter and the receiver. A team from UC Berkeley has this to say:

These signals look similar to what we think might be produced from an extraterrestrial technology. They are narrow in frequency, much narrower than would be produced by any known astrophysical phenomena, and they drift in frequency with time, as we would expect because of the Doppler effect imposed by the relative motion of the transmitter and the receiving radio telescope

The Kepler satellite

Kepler has been remarkably successful in detecting exoplanets. It has achieved much success by looking at ‘transits’, or the passage of planets in front of their suns. Kepler needs four transits to confirm the existence of an alien planet. This takes around 3.5 years.

So, tantalizing it might seem, but it’s just not true. Kepler has not yet found alien life, leave alone intelligent alien life. But the search continues…

Reference and more info here: http://news.discovery.com/space/is-there-a-seti-signal-coming-from-a-kepler-exoplanet-120106.html
Berkeley link: http://seti.berkeley.edu/

Discovered: Two Earth-Sized Planets Around A Sun-Like Star

Scientists report the finding of true two Earth-sized planets orbiting a star very similar to the sun, using the Kepler telescope. The discovery was announced today. Named Kepler 20e and Kepler 20f, these are the smallest planets ever to be discovered.

An artist's impression of Kepler 20e. Image Courtesy: NASA/JPL/Caltech

The location and details

The stellar system is located 950 light years away from Earth. Both planets are about the size of Earth, with one of them being slightly smaller. This is important, since we now know that we can indeed detect planets the size of Earth in another stellar system. In the future, we might indeed stumble upon a planet, the size of the Earth, with conditions similar to our home.

The planets orbit the star a bit too close for comfort and the surface temperature is too hot to sustain the kind of life we know. It’s not a true twin of the Earth, but this does indeed bring us tantalizingly close to finding one.

+2 for Kepler

This is again a feather in the burgeoning cap of NASA’s Kepler space telescope, which was recently lauded for finding a planet, called Kepler 22b, orbiting another star in the Goldilocks region.

Both Kepler 20e and 20f are rocky planets and have an estimated mass of 1.7 times and 3 times the mass of the Earth respectively. While Kepler 20e lies at a distance of 7.5 million km away from the sun, making it 20 times as close to the star as Earth (150 million km), Kepler 20f, does slightly better at 16.5 million km. Kepler 20e takes a mere 6.1 days to complete an orbit around the star, while Kepler 20f takes 19.6 days.

There is no possibility of liquid water, or even an atmosphere on either of the planets. However, astronomers are hoping that, given the plethora of exoplanets being discovered, one will turn out to be just right’ for life.