Friday, 28 August 2015

A miniature mission to the Moon, and what the hell ARE those spots on Ceres?

A Miniature Moon mission  to search out lunar ice:
Over the last ten or fifteen years a quiet revolution has been going on in space technology: Like computers in the latter half of last century, they've been getting smaller - and the most popular of the miniature spacecraft is the 10cm by 10cm by 10cm cubesat.  This year has seen cubesats start to come of age, with a cubesat flying with a solar sail, cubesats flying to Mars, and now a cubesat based craft from Arizona state University is set to map water ice deposits on the Moon:


Latest pictures back from Ceres:
Five months ago the Dawn spacecraft pulled into orbit about the dwarf planet Ceres. One of the first things its team noticed - in fact something that had even been noticed by the Hubble space telescope from Earth - were some incredibly reflective spots punctuating the dusty surface. These were so bright that Dawn's camera had trouble seeing inside of then, due to the glare.
Above: Images of Ceres taken by Hubble - the bright spot is the mysterious bright spot in Occator crater. Courtesy of NASA  and Tom Caldwell.
But the Dawn mission is a billion dollar exploration vessel controlled by some of the finest so they've...they've..... oh I can't keep that up, dammit. We still don't know what the bloody things are.
Above: Dawn tracks the bright objects in Occator cater over the course of one day. Courtesy of NASA.
What do we know? We know they're bright, and we know that the brightest spots appear within Occator crater - and apparently are over a long tectonic-fault like structure...
Above: Occator crater, showng the fault lines that pass through it upper left. Courtesy of NASA.
We know that Ceres is rich in water ice, so subsurface water ice thrown up to the surface by an asteroid hit has been suggested - but we also know that ice would rapidly evaporate into space. So another suggestion that has been that they are some sort of salt deposit. The salt would last longer, although not forever - it would still get wiped away my meteorite strikes eventually. But either way the question is how did it get there, and why that spot? To add to the mystery are reports from the Dawn team that they've seen clouds or hazes over the crater. So, as far as explanations go,The main contenders so far seem to be:

Exposed ice
This would make a lot of sense, as  Ceres has lots of ice. Evaporating ice might also explain the hazes. But ice would need to be replenished regularly by some mechanism

Salts
Salts could have been left behind in a more ancient time when Ceres core was still warm and salty water could travel to the surface. 

Venting
Although this would be the most exciting possibility of all it's also the least likely. A while back the team thought they'd seen something - perhaps a plume from a vent - rising over the edge of Occator but this has stayed unconfiremed. Although most computer models suggest Ceres core froze solid aeons ago, a ew do allow some ectonic activity to continue, and an actve Ceres might also mean one with a subsurface habitable zone.

We'll know more soon, as images of Occator and its mysterious bright spots should arrive in the coming weeks!

As long as they're not neon signs saying 'drink Starbucks coffee....'

Elsewhere on the internet:


Tuesday, 18 August 2015

The exploding glaciers of Pluto

A month and a half ago the (dwarf) planet Pluto was only a dot in the eye of the Hubble Space Telescope. Now New Horizons has flown past Pluto, making the dwarf planet its first stop as it explores the Kuiper belt, and this is the result:

Above: The New Horizons flyby of Pluto, revealing a strange nw world to us - and this is just the first of New Horizon's targets... Courtesy of NASA.

It's an entirely new world, never seen before, so there's lots to get scientists scratching their heads. But right away something leapt out as odd in a different way - because of its very familiarity: Pluto has what looks a hell of a lot like glaciers. In case you don't pay a lot of attention to geology, glaciers a flows of ice that wind their way across very cold landscapes. For glaciers to flow - on Earth at least - a certain amount of the ice must be warm enough to contain a small amount of water.
Above: A terrestrial glacier, spilling out onto a tundra plain.
On Pluto all the water ice is deep, deep, frozen - as hard as rock. So for these glaciers to show the signs of flow they have they must be made of something with a far, far lower freezing point - and the most likely candidate is nitrogen, the gas that makes up most of our (and Pluto's) atmosphere.
Above: Glacier-like landscapes on Pluto that seem to flow - at temperatures far, far, to low for water ice to move at all. Here one is caught slowly flowing in to fill a crater in a huge, slow motion, flood. Courtesy of NASA.
The (apparent) presence of nitrogen glaciers suggests  the physical and chemical behaviour of Pluto's surface might get very, very odd indeed. Nitrogen, when it freezes, has some tricks that water doesn't. One thing is that the ice can have two kinds of molecular structure, and when it  changes from one kind to the other... well, watch the video...



As the seasons change on Pluto the type of ice that is most stable changes. The nitrogen ice will always seek out the most stable form so... well imagine the explosive reaction that happened in the video happening all across a massive glacier. I have no idea what the glacier would do, but at least the images of Pluto don't look like the dwarf planet exploded.

These glaciers might be a hint at more than just alien physical processes and chemical reactions. It could be a hint of a habitat for Plutonian life. Y'see, if these glaciers are made of frozen nitrogen, and flow like glaciers on Earth, then thirty meters or so beneath the surface they are probably riddled with veins of liquid nitrogen. Recently, computer simulations have shown that cell membrane-like structures could exist in the frigid liquid methane seas of Titan, and it's been known for a while that there's something on Titan is consuming hydrogen and acetylene.
So is it much of stretch to imagine some Plutonian equivalent to life operating in subsurface pockets of liquid nitrogen? Many microbes live beneath the surface of Earth's glaciers - although that's not really a fair comparison. Still, while it's a far fetched idea, it was suggested a long time ago that liquid nitrogen chemistry might support life based on silicon instead of carbon.

If that's a bit much of a stretch (and I'll admit I've been more imaginative than scientific with it) a more prosaic line of though suggests there might be a habitable zone beneath Pluto's surface: Pluto is loosing its nitrogen atmosphere at a rate of 500 tons per second... yet it still has an atmosphere. That suggests some sort of internal activity is replenishing it, and internal activity might well mean enough heat to keep a subsurface ocean, like Jupiter's moon Europa.

It's very likely that I won't live to know the answer - ships to Pluto don't exactly grow on trees. But one thing we've learnt is to expect surprises, so who knows what may be lurking beneath that pinkish surface....

Monday, 27 July 2015

I'm off on my honeymoon!

Above: A recently released high resolution map of Pluto's surface. courtesy of NASA
Hi everyone, I've just got married so I'm away on my honeymoon until mid august now, but don't worry I'll be back with a vengance before you know it.

In the meantime, here are a few predictions for the time period I'm away:

  • As  more data comes down from New Horizons our Picture Pluto will get more complex, including the presence of prebiotic molecules on the surface and near surface.
  • There will be at least one speculative article published on the possibility of life beneath the surface of Pluto - either earth like life near the core or life in cryogenic liquids (IE liquid nitrogen or methane) in the near sub surface.
  • Charon will be revealed to have had a tortured and geologically active early history.
  • Ceres will become a scientific arguing point, as evidence for activity and 'hazes' there is presented to the world.
  • The Philae lander will continue to make intermittent contact with its Rosetta mothership.
  • I will spend the next three weeks on a beach doing solar astronomy with my tan. :D
Be happy everyone,

John

Wednesday, 22 July 2015

Water on Ceres?

Update: you can find the actual talk (mentioned below) by Chris Russel here, or if that's not working try going through the websit, here

I am getting married on Sunday, then jetting off on my honeymoon, so there's not a lot of time for me to write at the moment. But the universe has, it seems, given me the chance to leave you all with a real - and possibly game changing - mystery:

Is the dwarf planet Ceres hiding an interior warm enough to have an ocean?

Above: The still unexplained bright spots in Occator crater - they are so bright they are visible to Hubble, orbiting Earth
Right now Ceres is being studied by the Dawn mission, which had previously stopped at the giant asteroid Vesta. It's been guessed for a long time that Ceres could have a significant amount of water ice in its interior, and computer models have predicted that it could have retained enough heat for an ocean to persist near its core for billions of years. Spectral scans from Earth have found water related minerals onn the surface.On top of that the Herschel space telescope has caught a plume of water vapour over the Cerean surface.

So when Dawn arrived we weren't sure what we were going to find... and Ceres's still surprised us: the surface is spotted still unexplained, ultra reflective, bright spots. The brightest of these is located in Occator crater, and is basically just baffling. Although it sits at the bottom of the crater the bright area has seemingly been observed over the rim of the crater, as if it were elevated somehow.

Last night a couple of tweets from planetary science journalists surfaced:

"Andy Rivkin ‏@asrivkin:
Russell: Can see haze in crater with bright spots at some local times. Bright spots "indicate Ceres is active today." #nesf2015


Chris Russell at the NASA Exploration Science Forum"


...and then this one (link here):

"Whatever the cause of the bright spots, Ceres is active today".
 
Above: A 3D model of Occator crater, as seen at Chris Russels update.

These have both come out of Chris Russells Dawn update at the Exploration Science Forum at NASA Ames.
A few hours later this report (link here) from Emily Lakdewalla of the Planetary Society surfaced.The gist of the update is that the Dawn team have seen some sort of haze over the Occator crater, at various times. The haze is confined to the crater itself - and on a world with next to no atmosphere it's hard to come up with any other explanation than gas escaping from some sort of internal volcanic activity.

If Ceres is still active then, unless we've got something very wrong (always possible) there's probably still liquid water - and a possibility of life - lurking beneath the surface. And if stuff is escaping onto the surface we could examine that liquid water (perhaps) with a follow up mission to Dawn.

Sometimes these big announcements don't work out - this could be a camera fault, image processing artifact, or there might be some other explanation. But it's a good note to go away on, so I look forward to telling you all whether this discovery has been confirmed or not when I come back in three weeks....

Take care all,

John 

Saturday, 18 July 2015

What in the worlds made Pluto and Charon so complex?

Above: An artists impression of Charon, as seen from Pluto.
OK, at this point the New Horizons flyby of Pluto is well over. Data is trickling back to Earth at a steady rate, and this will be the norm now for several months at least. So I promise that this will be the last post where I geek out over the latest results to trek across deep space and arrive home (cough, cough)... but.....

Yesterday (Friday 17th July) NASA held a press conference on... all kinds of Pluto-y things: Firstly, the Pluto 'heart' where New Horizons has confirmed presence of carbon monoxide ice covering it, the only such high concentration on the planet. Carbon Monoxide is actually pretty rare across the rest of Pluto - and one part of the heart has so much the spectral signature is visible from Earth. Why it should have so  much really isn't clear, but it's possible there's a CO source in that region - which would indicate some kind of internal activity breaking out to the surface...

Above: The area of the 'Pluto heart' with the intense carbon monoxide ice signature. That's a lot of CO in one spot.... Courtesy of NASA
Another huge plain, Tombaugh Regio, is  broken into massive polygon shaped plates. Along the edges of the polygons are some sort of  cracks.... as well as weird mounds that almost seem to be growing out of them, and an unidentified dark material. Some of the cracks have ridges running along their centres:

Above: Some of the cacks with central ridges, indicating rowth, perhaps.

Above: Tombaugh Regio. The black things that look like they're growing out of the cracks are hills made of an unknown black material. Courtesy of NASA.
Origin, and precise shape of the strange hills is unknown. There're some sign that they rise above the surrounding plains, and the geophysics have two theories; They could be erupted from below, like volcanoes or could be harder material left behind as erosion from above lowers the height of the plain. They are - very unofficially - slightly leaning towards the eruption idea, but only very slightly:
“This terrain is not easy to explain,” said Jeff Moore, leader of the New Horizons Geology, Geophysics and Imaging Team. “The discovery of vast, crater less, very young plains on Pluto exceeds all pre-flyby expectations.” One odd idea being bandied about by astrogeologists is that some of these features might be liquid carved, like the liquid methane rivers on Titan, This is defiantly an odds against idea, but there are some liquids that might exist on Pluto

Other news comes from the probe's analysis of Pluto's atmosphere, which is made of nitrogen, and is being stripped away by the solar wind at 500 tons per second. That rate of loss compares unfavourably even to Mars ( which looses its air at at 1 ton per second). Over the lifetime of Pluto that's equivalent to a loss of several thousand feet of nitrogen ice - assuming the atmosphere is being replenished by evaporating ice. The atmosphere s around 1000km deep - almost as deep as the dwarf planet is wide - and the winds in its lower levels strong enough to move particles and cause erosion, which means that Pluto's surface will be eroded and shaped by them. 
Some evidence of this has already been picked up as streaks on dark material, apparently blown by the wind, seen on surface. The origin of the dark stuff might be due to geyser like eruptions, or it might be entirely due to wind eroding deposits of dark material - there's no evidence of eruptions but the team will be looking.

Above: Mysterious streaks of windblown material across the frozen plains of Pluto...possibly a hint of subsurface activity?
On to the moons of Pluto: Nix as been imaged for first time - it's shown to be about 25km across, and about twice as long as it is wide:
Above: Our first view of Nix, Courtesy of NASA

....and Charon has a very strange looking mountain with a 'moat' all around it - the feature has everyone utterly baffled. But we'll know more soon:
Higher resolution images are coming, as well as data from other sensors like Charon atmosphere data (coming Sunday).

Above: Charon, showing off its weird mountain (upper left), courtesy of NASA.

Elsewhere on the Internet:
Jupiter twin
ISS crew man lifeboats
Continental crust on Mars
Zebra stripes in space

Wednesday, 15 July 2015

The news from Pluto....

The first batch of the data New Horizons collected during its fly-through of the Pluto system has made it home. I think the best way to sum up the reaction of the science team at this evenings press conference is in the words of Kathy Olekin, New Horizon's deputy project manager : "This exceeds what we came for!"

First let's look at what the team were able to say -and show - about the largest moon, Charon:

Above: Charon, seen up close for the very first time in our solar systems 4.5 billion year history. Courtesy of NASA

Charon's dark northern region (known informally as 'Mordor'), seems to be covered in a thin layer of dark material - although why it's gathered around Charon's north pole isn't clear.  Massive cliffs stretch for hundreds of kilometres, and on the upper right a chasm perhaps nine kilometres deep can be seen. The surface has very few craters, just a few here and there. It all suggests a world whose crust has been cracked open by immense internal forces, and had its surface covered over by material welling up from deep inside -  and in the (geologically) recent past. On earth that would mean volcanoes of molten rock. On an ice world like Charon that means cryolava - a mixture of liquid water and other low temperature materials, like nitrogen and ammonia. It might imply the existence of an ocean buried deep beneath Charon's crust....

On to Pluto:
First a name for the dark plain on Pluto that tickled me, as it refers to a character from one of my favourite horror stories: Cthlhu Regio. Plutonian mountains, 3500 meters high and probably made of water ice (based on how strong they must be to get so tall), have been found. But they're covered in nitrogen and methane ice - and almost no craters are on them, so they are geologically young, 100 million years old or less.

Above: A video showing where the newly discovered mountains lie on Pluto. Courtesy of NASA.

Above: The mountains seen with a scale bar, and showing one of the huge pits in the surface. Courtesy of NASA.

Pluto also has huge, oddly puckered, dimples in the surface. We have no idea what they are, but here's one idea:Alan Stern and Keisi Singer have had a paper accepted today where they argue that the nitrogen on Pluto - both atmospheric and surface ice - might need an internal source to sustain them... so perhaps these are the sites of huge vents, or cryovolcanoes. Saturn's moon, Enceladus....

Above: Strength of the methane signal on Pluto. Green is more, red less. Courtesy of NASA.
There are also some really bizarre folded landscapes, that well, look like nothing I can really name. However it reminds me slightly of the active south pole of

Above: Enceladus' south polar region.Or possibly a monstrous brain... nah? Courtesy of NASA
It seems, right away, that both Pluto and Charon are hosts to internal activity, so what could be powering it? The ideas put forward at the press conference were:

1. Radioactive heat... (All bodies generally have radioactive materials in their deep interiors)
2. Body could probably store heat of formation for a really long period of time. Maybe there's an ocean (implied sub-surface) that's freezing and the heat released from it, is melting the crust..
There's a lot more data to come; New Horizons will be downloading for months yet. The other sensors may well have been able to detect organic molecules,  Methane, Ethane, Propane, polycylic hydrocarbons etc. It's not a given yet that either Pluto or Charon do have internal oceans, but there's clearly some source of geological energy!

There will be another conference to reveal more of the data that is streaming down on Friday - but until then you can watch the whole of today's conference here.

I think I'm justified in saying that with New Horizons at Pluto, Dawn at Ceres, Rosetta/ Philae at comet 67/P, Cassini at Saturn, Orbiters and Rovers at Mars, and other craft on their way to worlds like Jupiter... it's a really good time to be a space exploration geek!


Tuesday, 14 July 2015

Some quick notes: New Horizons survives hazardous passage through the Pluto system, control team now eyes the next target....


Above: Images from new Horizons approach to Pluto.

There's so much going on with the New Horizons mission right now that it's hard to take it all in - there's a lot of data still to come home, and the ground control team are already thinking about the next world in the Kuiper belt they want to visit. But here're a few quick notes that I've been able to gather from the internet scuttlebutt:


  • Data from the flyby will begin coming down today, and will include huge images of both Pluto and its biggest moon, Charon.



  • There will be a media event at about 1900 GMT where NASA will release some more data.


Above: one of the first attempts at a colour image of Pluto, using data from various new horizons instruments. Courtesy of ZLD on unmannedspaceflight.com