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Tuesday, 20 October 2015

Did life begin amidst giant asteroid strikes?

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Tiny flecks of carbon, preserved in Zircon crystals close to four billion years old, may have pushed back the earliest known life on Earth by a seemingly paradoxical amount. The tiny pieces of carbon might be microfossils - preserved remains of microbes caught inside the zircon crystals when they formed. Analysis of the ratio of carbon isotopes inside them suggests they're of biological origin, although carbon isotope measurements aren't conclusive proof of life: Other processes can duplicate the isotopic signature. But the amazing thing - if further investigation shows that this is true - is that this result would push the origin of life back to the time of the late heavy bombardment, 4.1 to 3.8 billion years ago, when Earth's surface was being pummelled by massive asteroid strikes on a daily basis. 

It's hard to see how life could have survived in such an environment. One possibility is that asteroid strikes themselves may have thrown microbe bearing rocks into space, where they would have been preserved before their orbit brought them back to Earth when the environment had calmed down (this is a variation of an idea called lithopanspermia) - if that happened then some of those ancient-microbe-bearing rocks should have landed on the Moon, and still be waiting there. Another is that the asteroid strikes opened fractures into the deep subsurface of the planet, allowing primitive life to retreat deeper into the planet, which brings us to...

Above: During the late heavy bombardment massive steroid strikes would have happened at an incredible rate, never giving the environment a chance to stabilise.

Fractures on the Lunar surface might tell us how life's first home formed 

The Moon was also caught in the late heavy bombardment, and because the Moon's surface is still fairly well preserved from its earliest days it's an ideal place to study just how mashed up the surface of a rocky planet would have gotten (technically this is called 'porosity' or how many holes and gaps the subsurface has) during the late heavy bombardment. Although the Moon's surface has evolved since then it's geology is still far better preserved than Earths:
Jason Soderblom, a research scientist in MIT’s Department of Earth, Atmospheric and Planetary Sciences, says the evolution of the moon’s porosity can give scientists clues to some of the earliest life-supporting processes taking place in the solar system.
“The whole process of generating pore space within planetary crusts is critically important in understanding how water gets into the subsurface,” Soderblom says. “On Earth, we believe that life may have evolved somewhat in the subsurface, and this is a primary mechanism to create subsurface pockets and void spaces, and really drives a lot of the rates at which these processes happen. The moon is a really ideal place to study this.”

Above: The Moon. It's full of cracks and holes, who'd have thunk it? Courtesy of ESA.

The IAC 2015 in Jerusalem, hosted by the Israel Space Agency, ended on Friday with a special session examining the latest news about running water on Mars. NASA’s Jim Graf, the former Mars Reconnaissance Orbiter Project Manager said "....we found hints that point to a wetter past on Mars. We also found different minerals that indicate volcanic activities. We know that at a certain point the minerals developed at a higher altitude and then flowed down to lower regions.” However, the (very likely) traces of liquid water on the surface today raised problems as well as opportunities, specifically the problem of contamination:  “If we find life, we want to make sure that we weren’t the ones to bring it there,” warned Dr Graf.

Above: An animation of the suspected flows of water on the Martian surface, NASA/JPL.

Note the inverted comma's - they're important because it's still a very, very long way from proven that the strange events around the star known as KIC 8462852 aren't just a previously unknown natural phenomena. However, the strangeness of what has been seen so far - mysterious dips in the star's light that don't fit any natural cause without invoking some really big coincidence - has been enough to get the Allen Radio telescope array turned towards it, to listen for any evidence of artificial activity. "We are looking at it with the Allen Telescope Array," said Seth Shostak, a senior astronomer at the SETI (Search for Extraterrestrial Intelligence) "No problem with that; I think we ought to, for sure," Shostak told But, he added, "history suggests we're going to find an explanation for this that doesn't involve Klingons," pointing out that astronomers have found artificial seeming signals in the past that turned out to have natural causes - such as pulsars which were originally labelled 'LGM' for 'Little Green Men'.

Above: The dishes of the Allen array. Courtesy of SETI.

Here's a truly fascinating snapshot of space history: An article on the (now declassified) original engineering report written after Yuri Gagarin's first flight into space. To just give you a little taste of the conclusions that can be drawn from it:
  • It was very much a military effort: Gagarin's spaceship was actually an offshoot variant of a new spy satellite.
  • If he had  landed off target (which he very nearly did due to a faulty engine valve), he would have had to survive without any supplies.  
  • The spherical descent module carrying Gagarin, and the conical instrument module, which lacked a heat shield didn't separate as planned, putting the manned descent module in considerable danger.

A good summary of the results from New Horizons (so far)

If you're anything like as a big a space geek as me then you've been following the data sent back from New Horizons fly by of Pluto with a permanent expression of 'wow'. But the link above leads to a nice, concise, summary of the Major finds of the mission to date, including those about Pluto's smaller moons. According to internet scuttlebutt, the images of Kerberos, the oddly dark moon of Pluto, should come down to Earth this Friday.

Above: Pluto. Courtesy of NASA/JPL.

How the James Webb Space Telescope will help us explore Mars

This  an interesting paper, if you have the time to give it a proper read: The James Webb Space Telescope is often touted as a successor to Hubble, but will actually be a very different instrument, working at infra red frequencies and providing astronomer with a WHOLE new suite of abilities. One of these will be to study the planets in our own solar system in great detail - and of course, the paper takes Mars as it's example. JWST will be able to do things like measure changes in atmospheric water vapour over time, and search for chemical changes, hydrated features and ice on the Martian surface.

Above: Afull size mock up of the JWST. Courtesy of NASA/JPL.

NASA puts out a pre-solicitation notice for design studies on its asteroid capturing robot

Just brief not: NASA has put out a 'pre solicitation notice' for design studies on the robotic probe that will capture a boulder from the surface of an asteroid and tow it into an orbit around the Moon. This is part of it's 'Asteroid Redirection Mission' project, which  is partly about asteroid science, and partly about NASA practising complex tasks in deep space - tasks which will be needed for a mission to Mars. ARM's objective is to have  a manned spacecraft rendezvous with the asteroid fragment astronauts crawl over it too study it up close - a possible practise run for a visit to Mars' tiny moon Phobos. The notice basically means they're giving anyone who might be interested in building the probe the heads up to start getting their bids in order.

Above: An animation of the ARM. Courtesy of NASA.

Lastly, two stunning pictures: 

Courtesy of Carlos Fairbairn via APOD.

Courtesy of Jonathan Tucker.
...oh and, not that I'm wetting myself like an over excited five year old about this, but the new Star Wars trailer is out!

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