Sunday, 14 February 2016

Possible (and I can't emphasis that word enough) evidence of ancient bacterial activity on Mars

Above: A comparison of the 'micro-digitate' structures, on Earth and Mars. Courtesy of NASA.

An interesting theory has been put forward in a paper presented, at the 2015 AGU fall meeting. Titled " Micro-digitate Silica Structures on Earth and Mars: Potential Biosignatures Revealed in the Geyser Field of El Tatio, Chile", the gist of it is this: Certain types of volcanic spring produce deposits of silica round their edges. Those deposits can take on these strange 'micro digitate' structures, for no really obvious reason - and the paper has an explanation that could lead us to evidence of bacterial life on Mars: The 'digitate' structures are due to the action of bacteria,  growing in the forming deposits.
If these weird looking structures did form through microbial action it would be big news for the search for Martian life, because the extinct 'home plate' geothermal spring which was surveyed by the Spirit Mars rover.  The abstract is here, and Universe today has done a nice in-detailed breakdown of the theory here.

Friday, 12 February 2016

Gravitational waves and floating hills..

Isn't this typical: I go on holiday for a week and everyone starts making mind bending advancements in astrophysics and space technology,while you're stuck up in the Scottish highlands with the amazing mountains, wildlife, and ski slopes....

Yeah, Scotland you suck, and you're ugly too....

.... fair enough, I had a good holiday and I'd recommend Scotland to anyone who likes holidays that are bit more adventurous than just lying by the pool. But some of the things that have happened this week have been momentous, so lets have a quick look at the two stories that really caught my eye, before it's back to business as usual:

Gravitational wave detection:

This is the weeks big BIG news, and everyone says so. Lots of them then ask 'what the hell are gravitational waves' and they're right to do so, since this isn't a topic that's covered in high school physics. Which is odd, because it's actually very simple. Waves occur in lots of things: Sound waves in gasses, surfable waves in water, electromagnetic waves (like radio waves and light waves) in electric and magnetic fields. Gravitational waves are just waves in space itself.

A sound wave is a pressure wave, so as it passes you the air pressure gets higher, then lower. Ocean waves are up /down motions in the water,so as they pass the water gets higher, then lower. Gravitational waves are distortions in space-time, so as they pass space itself stretches and squashes. As one hits you, you get slightly taller and thinner (very, very slightly), then slightly shorter and fatter (Universe today has some good animations explaining them, here).

Above: If you looked at a ring of dots just as a really huge gravity wave passed through them, you'd see them flex like this.

Space-time itself rings like a bell and, thanks to the fact that all waves have some things in common, we can actually translate the gravitational waves into audible sounds....

Above: The gravitational wave signal seen by LIGO, converted into audible sounds. It sounds rather nice for something that's travelled across a billion light years. Courtesy of Georgia Tech.

The waves are incredibly tiny: The ones that were picked up had travelled over a billion light years, and by the time they hit earth they were only strong enough to distort space by about 1/10,000 of the width of a hydrogen atom. But the incredibly sensitive detectors built to detect them, the LIGO detectors, independently saw the signal at the same time, which is a good sign that this is a real detection (and the reason why two detectors were built in the first place)

What does all this mean, aside from being a scientific curiosity? 
It gives us an entirely new way of 'seeing' the universe, other than electromagnetic waves (like light) and particles - in principle we can now see through light years of gas and dust, and watch the most powerful events in the history of the universe. the signal that was picked up was from two black holes, each weighing tens of times more than the Sun, hitting into each other...

Above: A simulation of what the event seen by LIGO would look like close up, courtesy of SXS Lensing

But it's also a final confirmation of Einstein's theories of gravity - confirming that they were on the money, in almost every respect, as far as we can measure.

Floating hills on Pluto:

Above: The clusters of floating hills on Pluto's sea of glaciers. Courtesy of NASA.

Last year the New Horizons spaceship gave us our first close up view of the dwarf planet Pluto. One of the surprises it gave us was the discovery of Sputnik Planum, a vast 'sea' of nitrogen ice glaciers. On Earth glaciers are made of water ice, which seems solid enough but flows at large scales. That allows huge 'rivers' of ice to flow across the plains of Antarctica and down the sides of mountains. On Pluto water ice is far too hard to flow at all, because of the much lower temperature. But nitrogen ice is still squishy enough to form glaciers in such frigid conditions - and unlike the isolated glaciers of Earth, Pluto's flow into a huge sea of slightly squashy nitrogen ice. 

That sea does some things we don't entirely understand, like form huge cell-like patterns on its surface (probably due to very slow convection currents), and elliptical pits that all line up.

Above: The cell-like patterns on the surface of Sputnik Planum
Now a detailed study of the latest images to be transmitted home by New Horizons has shown that it does something else: It actually has hills that float on it!
On Pluto the hills are made of water ice frozen super-hard. But it's still water ice, and water ice is less dense than nitrogen ice, so whole hills have broken off from the coastline if Sputnik planum and gone floating away, a bit like a bizarre reflection of Earth's ice bergs:

The hills are gathered in clusters at various spots, and seem to drift on the glaciers until they run aground somewhere.... or wander the sea forever. But this is all pretty day to day for the New Horizons team - I can't wait to hear about Pluto's next weird surprise!

Elsewhere in the universe:

James Webb Space Telesope passes milestone

Massive rogue planet found

Thursday, 4 February 2016

Goodies from the Chinese Moon lander Change' and rover Yutu.....

Above: Yutu sets off into the lunar wilderness.

I'm away for the coming week, so there'll be no posts until next Friday at the earliest. But before I go I'll leave you with one of these that ideas I love because of how simple yet effective it is.

50 Years ago on Wednesday humanity got its first pictures back from unmanned probes sent to the Moon. The most recent landings there were the Change lander/ unmanned observatory, and the Yutu rover - and the Chinese space agency has released a whole bunch of new pictures from the ongoing mission.

Above: Yutu does Change' a farewell doughnut.

The Yutu rover took a panorama, as a series of pictures, of it's landng site on the Moon, the Change lander/lunar observtory, and the landmarks  around it. 

These have been very skiillfully stitched together by Justin Cowert from unmannedspacecom, to give the full panoramic viw of the Moon's black sky and razor edged horizon. All an amazing feat all on it's own, but then it was taken up a notch when it was uploaded to RoundMe (here), a website that specialses in presenting all sorts of panorama's in a very unique way. 

And in this case it may be the closest you'll ever get to knowing what it's really like to stand on the Moon....

Elsewhere in the universe:

Luxemburg supporting space mining

NASA satellites investigate dmage patterns in Nepal

Wednesday, 3 February 2016

A flight over Ceres!

Above: Occator crater with its mysterious bright patches. Courtesy of NASA.

The Dwarf planet Ceres is known to space exploration as king of the asteroids - and, now that the Dawn space probe has begun exploring it in earnest, as a world that throws up two mysteries for every one that is solved: From the strange bright patches and volcanic looking terrain, to totally unexpected mists over Occator crater, to chemical evidence suggesting it might be an immigrant from the cold outer solar system, Ceres seems determined to both surprise us and keep its secrets as long as it can.

Above: A size comparison between Ceres, Earth, and the Moon.

And long it may keep them, as this small and distant wold is unlikely to be visited by humans for many decades at least. But this week Dawn's framing camera team at the German Aerospace Center, DLR, gave the whole world a brief taste of what being on such a mission might be like, when they released this high quality simulation, based on Dawn's data, of a flight over Ceres:

The virtual flight path was picked to give an impression of how the Cerean terrain changes from place to place."The simulated overflight shows the wide range of crater shapes that we have encountered on Ceres. The viewer can observe the sheer walls of the crater Occator, and also Dantu and Yalode, where the craters are a lot flatter," said Ralf Jaumann, a Dawn mission scientist at DLR.

Tuesday, 2 February 2016

How the Moon influences the weather

The Moon influences the tides, controls the length of the day, controls the biological cycles of certain creatures, and of course, werewolves*. But, for the first time, it has been shown by Tsubasa Kohyama and John M. Wallace that Earth's nearest neighbour can exert control ovr the weather. Specifically their investigations have found that the Moon influences rain fall, in a small but definite way. "As far as I know, this is the first study to convincingly connect the tidal force of the moon with rainfall," said Kohyama.

Yep, you an now literally blame he rain on the Moon. drop in every hundred, at least.

The way it works is down to gravity, and is not a million miles away from ow tides work: When the Moon is overhead, its gravity causes Earth's atmosphere to bulge toward it, like a tide of air, so the pressure of the atmosphere on that side of the planet goes up. Higher pressure increases the temperature of air near the surface. Since warmer air can hold more moisture this makes rain - which happens when the air has too much water - harder to form.

Filled to capacity.....

The effect is measurable, but, today, very small. "No one should carry an umbrella just because the moon is rising," Kohyama said.The effect could be used to test climate models, checking if they're good enough to reproduce how the pull of the moon eventually leads to less rain. A further twist to the tale is how this might change our understanding of ancient Earth: In ancient times The Moon was closer, and raised more powerful tides - becoming truly monstrous if you go back far enough. Would the dinosaurs, for example, have been able to predict some aspects of the weather based on the Moon's stronger influence? We may never know, but now the idea has been raised researchers will be looking for ways to find out. 

Above: I'm not sure T-rex would have cared very much... but you never know......

Even today the Moon may be pivotal in easily influenced weather systems. Wallace plans to study the Moons' meteorological effects further: Some categories of rain may be more susceptible to the influence of the Moon, and the frequency of rainstorms may show a lunar connection.

Maybe what's out there has more of an impact down here than we ever realised...

Monday, 1 February 2016

Liquids on Pluto, its huge climate changes, and NH next target....

Last week Alan Stern spoke to the SBAG about the latest New Horizons plans (latest Adobe version needed). Alan is New Horizon's principle investigator (basically he's the closest thing an unmanned probe gets to a captain), Alan Stern. I was hoping to put up a youtube version of this talk, but the only version I can get my hands on needs the latest version of Adobe (gettable from here). For those of you who don't or can't get Adobe, here're the highlights of the talk, with some stills:

  • PEPSSI and SWAP instruments made important detections, there's a paper about it submitted to science magazine.
  • The dust detector will be the first to take readings out to 35 AU and kuiper belt
  • 16 months to beam all data back (4 months if they had the dsn to themselves)
  • They got good data on all of daylight Pluto, not just the side that got imaged at closest approach:
    • Black and white optical data of far side at 40km per pixel resolution.
    • UV and colour data, with 200 km footprint, of the far side - good enough to do regional colour and composition analysis.
    • The best resolution of encounter hemisphere is 70m/pixel.
Above: All the sunlight views of Pluto. Only the south pole was never seen due to permanent darkness.

  • New horizons has revealed a very complex world
    • Young icy plains - especially the glacier sea of Tombaugh regio.
    • Sublimation pits in the glaciers
    • Dark, very red, plains devoid of volatiles
    • Tectonic features: Scarps, faults, and rift valleys.
    • What look like shield volcanoes
    • A complex atmosphere

  • The atmosphere shows:
    • Possibly evidence of huge pressure pulses on the surface, from near zero millibars up to 100 millibars of atmosphere (more on that below)
    • 24 plus haze layers, probably made of tholin particles, up to 230 km height.
    • Very similar to Titan's extended/detached haze layers
    • They're blue in colour ,as seen from behind the planet via scattering via Raleigh scattering. 

    • The scattering is so bright the NH team can use the hazeshine to see the night side at high resolution, and are mapping large areas that way- an unexpected bonus!

    • Atmosphere is colder, and more compact, than expected - this result is from the by solar UV occultation experiment.
Above: The results of the solar UV occultation test.

    • Atmosphere loss rate is 1000 to 10000 times lower than expected - much more like a planet than a comet, which was the expectation..

  • A false colour, dynamically stretched, view of the surface shows....
Above: A false colour, colour sharpened, view of Pluto.

    • Red stuff (almost certainly organic) fills the mountains around glacier sea.
    • The glacier sea fills an ancient impact basin
    • The mountains are water ice, and are chaotic in structure; They seem to float on an ocean of frozen nitrogen.
    • The mountains have snowcaps of methane.
False colour close up.

  • The glacier sea has no craters (so it's under 10,000,000 years old.
  • It has a 'cellular' pattern on its surface.

  • This pattern is most likely due to convection in the ice (it's warm at bottom, like boiling syrup or a lava lamp)
  • The glaciers are active, not preserved, and are seen to flow around obstacles
  • Pluto seems to have , or have had, a Nitrogen cycle like Earth's water cycle
  • The southern glaciers have pits:
Above: Pits in the glaciers
  • Some pits are 100 meters deep or more, and show very, very, black matter at bottom.
  • The pits have possibly have eaten through into a layer below the glaciers.
  • Dendritic channels on the surface MAY indicate that liquids flowed on Pluto's surface in the past
Above: Dendrite channels.
  • This would be evidence of huge pressure pulses on the surface, from near zero millibars up to 100 millibars of atmosphere.
  • Shield volcanoes on surface, 100km wide, with very few craters on surface, indicating they are under a billion years
  • Pluto has young, old, and middle age terrains - which means Pluto has been active throughout its history - where's the energy coming from on such a small, cold, world?
  • Charon may have stolen atmosphere from Pluto during high pressure pulses, freezing it into dark polar cap
  • Charon also shows a complex geologic history
  • Organa crater on Charon has an ammonia ejecta blanket, possibly indicating subsurface fluids at one point.
  • Several of the little moons look like two objects merged:
  • The next target didn't get a name because Jim Greene dragged his feet getting the naming contest going, so it's called (informally) 'Jim Greene'
  • It's under 50 km wide
  • NH will arrive there on the1st Jan 2019
  • NH will come close enough to do science on 20 KBO's

  • NH will measure the heliosphere phenomena much better than Voyager.
  • After Jim Greene flyby Nh may go into astrophysics mode - seek microlensing events from extrasolar planets, and doing dust studies..
  • Here are the preliminary science objectives for Jim Greene:

Saturday, 30 January 2016

X-ray Aurora above Earth....

Above: The surprising view of an violently X-ray emitting aurora, that the INTEGRAL space craft got. Courtesy of ESA

ESA’s INTEGRAL space telescope usually looks into deep space at x ray sources, like black holes and neutron stars. But in November it got a surprise: As it turned to map a section of deep spacer in X-rays it saw a powerful X-ray emission coming from somewhere else: Earth's atmosphere.
The blast of X-rays was coming from the polar regions, where a storm of high energy particles from the Sun was crashing into our upper atmosphere, causing Aurora - these huge curtains of light in the polar sky:

As the high speed particles of a solar storm are funnelled by Earths magnetism into the atmosphere over the poles, different molecules and atoms  in the atmosphere glow like a flourescent tube to create these curtains,  typically in green and red. But auroras also emit X-rays, generated as the incoming particles decelerate - and on this occasion they shone so brightly in X-rays they blotted out the cosmic sources Integral was set to map.
That said the observations weren't a waste: The Earth's magnetic field and how interacts with the solar wind and storms is a source of mysteries to science - which is great, because it means we can use the space around Earth as a huge laboratory to test our theories on magnetism, plasma, and electricity. In fact whole fleets of unmanned probes have been launched to do just that.

Above: Results from ESA's SWARM mission, a fleet of space craft studying Earth's magnetic field.

What Integral saw will help NASA understand the pattern of electrons raining into Earth’s upper atmosphere, and they reveal interactions between the solar wind and Earth’s protective magnetic bubble. “Auroras are transient, and cannot be predicted on the timeframe that satellite observations are planned, so it was certainly an unexpected observation,” comments Erik Kuulkers, Integral project scientist. “Although the original background X-ray measurements didn’t go quite to plan this time, it was exciting to capture such intense auroral activity by chance.”