Chris Lintott’s Universe

I’ve already written a bit about Phoenix and mentioned that it’s heading for a site near Mars’ north pole, but where exactly are we heading? Doug Ellison has the details over at our Mars Live site.

Essentially, we’re heading for Northen Canada, but without the trees. Emily has the latest maps of the region, and gives the coordinates as 68.151N, 233.975E. Just out of interest, then, here’s Mars :

Credit : NASA / JPL / U. Arizona / Tim Parker

And here’s Google Maps’ highest resolution effort of the same coordinates on Earth

View Larger Map

Please do bookmark Mars Live and come and join us on Sunday night.

Update : Due to not paying enough attention, I put the target on the wrong side of the border between the Yukon and the Northwest territories. I’ve corrected it now; thanks for pointing it out in the comments.

I’ve really missed podcasting since the demise of Living Space’s previous incarnation, and the odd interview just isn’t the same. I’m delighted to say that I’ve managed to cajole the very busy and very knowledgeable Douglas Pierce-Price from ESO, the European Southern Observatory to join me. You can listen to our first show here :

or download it by right clicking here. We’ll have a web site up to go with this shortly, but in the meantime here’s this episode’s show notes.

In today’s show, Chris and Douglas talked about the how the planet Mars has turned out to be colder than expected, how the youngest supernova remnant in our Galaxy has just been discovered, and how astronomers have used a distant quasar and galaxy to take the temperature of the early Universe.

NASA’s Mars Reconnaissance Orbiter finds that Mars is colder than previously thought

Observations made with the Shallow Radar instrument (SHARAD) on the Mars Reconnaissance Orbiter (MRO) have shown that the outer shell of Mars is colder and more rigid that previously thought. SHARAD, which was built for the spacecraft by the Italian Space Agency, uses shallow subsurface radar to search for liquid or frozen water to a depth of about a kilometre in Mars’ crust. By looking through the layer of ice, sand and dust in the Martian north polar cap, the researchers could see through to the surface of the rocky crust underneath. It turns out that the planet’s surface is not sagging under the weight of the icy polar cap (as would happen on Earth), meaning that Mars’ outer shell must be very thick and cold. This result has implications for the search for liquid water hidden beneath the surface (and therefore also possible sites for life on Mars), as any underground aquifers would have to be deeper than previously thought in order for temperatures to be high enough.

NASA satellite finds interior of Mars is colder” press release at NASA.

Youngest Supernova Remnant in our Galaxy discovered

When a massive enough star reaches the end of its life, it can explode as a supernova. Theoretical models suggest that roughly two or three supernovae should happen in our Galaxy every century, but astronomers do not see as many as they would expect. The most recent observation of a supernova in our Galaxy was in 1604, of what is known as “Kepler’s Supernova”, and the youngest known “supernova remnant” – the shell of expanding material following the explosion – had until recently been Cassiopeia A. Observations of Cassiopeia A suggest that its parent supernova would have been observed on the Earth around 1680, but there are no definite historical records of it. Now, astronomers have found a supernova remnant in our Galaxy which has been caught at the new record youngest age of 140 years. The object, called G1.9+0.3, was first identified as a supernova remnant in 1985 by astronomers led by Dave Green from the University of Cambridge, using the Very Large Array (VLA) radio telescope in New Mexico. Then, in 2007, a team led by Stephen Reynolds of North Carolina State University observed the same object with the Chandra X-ray Observatory, and found that it was 16% larger than in 1985. The shell must be expanding very quickly to have grown so much in 22 years, which tells us that it must be very young. Follow-up observations at the VLA confirmed this result, and by looking at the expansion rate the astronomers were able to calculate the record-breaking age of the young supernova remnant. The supernova itself could not have been seen 140 years ago because of obscuring dust towards the centre of the Galaxy, but thanks to radio and X-ray observatories which can penetrate the dust, today’s team were able to find this example of the “missing population” of young supernova remnants.

Youngest stellar explosion in our Galaxy discovered” press release at NRAO.

Using a quasar and a galaxy to take the temperature of the early Universe

Astronomers have used a distant galaxy, and an even more distant quasar, to take the temperature of the early Universe. For the first time, they were able to detect a tell-tale absorption of light by carbon monoxide (CO) molecules in a galaxy so far away that its light has taken 11 billion years to reach us. The observations, made with ESO’s Very Large Telescope (VLT) in Chile, used the light from an even more distant quasar – a galaxy which emits intense radiation powered by a black hole in its core – as a ‘flashlight’ to study the galaxies between the quasar and the Earth. When the quasar’s light passes through each intervening galaxy, molecules in the galaxies absorb specific wavelengths of that light. Due to the expansion of the Universe and of the light itself over these billions of years, each galaxy leaves a fingerprint in the quasar’s light at different wavelengths. In this particular very distant galaxy, the astronomers observed the fingerprint of CO molecules, where the precise levels of absorption depend on their temperature, so the molecules act like a cosmic ‘thermometer’. Today, the Universe is filled with Cosmic Microwave Background radiation at a temperature of 2.725 K (about -270 Celsius). However, according to the Big Bang theory, the Universe was hotter in the past. The theory predicts that the temperature 11 billion years ago would be about 9.3 Kelvin, and the observations of the CO molecules gave a temperature of 9.15 Kelvin, plus or minus 0.7. This is an excellent match with theory, and an exciting new result which shows how interstellar chemistry in the early Universe can be used to tackle big cosmological questions.

A molecular thermometer for the distant Universe” press release at ESO.

Following my post over the weekend about the dangers of satellite building, here’s JPL’s excellent video about the Phoenix landing.

For those of you who’ll be online watching and waiting for Phoenix’s safe landing, I hope you’ll be able to join Doug Ellison (from Unmanned Spaceflight) and myself along with other experts for the ride; watch this space for stream details.

It’s exam season in Oxford, and I’ve made my first sightings of scared looking undergraduates in formal academic dress heading for the exam schools. I’m used, at this time of year, to waking up in the middle of the night tormented by dreams of the years that I sat through exam after exam after exam. This year’s been different, though, and instead of quantum mechanics and question choices I’ve been dreaming nervous dreams of landing ellipses and ice beneath the Martian surface.

In just over a week, if all goes well the latest probe to the red planet will touch down near the Martian poles and begin its study of the area. For many if not most of the science team preparing for the ride of their lives, this is a second shot at Mars as most were involved in the ill-fated Mars Polar Lander mission; that’s why the mission is called Phoenix, after the mythological bird that rises from its own ashes.

Landing at or near the poles, rather than at the safer equatorial region, brings a whole set of new challenges. The angle of entry into the atmosphere must be different, and Phoenix’s seven minute descent is a minute or so longer than that taken by Spirit and Opportunity, for example. Phoenix is too large and will be travelling too quickly to use airbags, and so will have to attempt a soft landing on what Mars Reconnaissance Orbiter, living up to the second word in its name, has revealed to be in parts rocky and even bouldered terrain.

I feel attached to Phoenix because of an amazing day I spent with the team behind her in Tucson a year or so ago. If the thought of those seven minutes of fear is keeping me awake, what must it be doing to the team who’ve been working on MPL and Phoenix for a decade or more?

Mars has a reputation for being an awkward planet to land on, and the overall success rate – especially when you compare it to that for Venus, which should be a much harder prospect – is surprisingly low. In the UK, I don’t think anyone who followed the story of Beagle 2 will ever forget it. Beagle 2 was an amazingly audacious project, attached to ESA’s Mars Express (which has, it shouldn’t be forgotten, been a wonderful success) designed to jump over several steps in NASA’s ‘follow the water’ strategy for Mars. While Phoenix is part of a series of missions designed to identify the possibility of life on Mars, find the best locations and then finally test there, the good ship Beagle tried to scoop the prize first time.

You know the punch line, I imagine, but there is good news. Many of the instruments and innovation that went on and into Beagle are being incorporated into Exomars, the European rover scheduled for launch in 2013. Exomars looks rather like its American cousins, Spirit and Opportunity, with six wheels and a tall mast with cameras on it, but it will carry a different set of instruments being less of a robot geologist and more of a robot astrobiologist.

I’ve been following the Exomars project for at least a couple of years now, and – apart from being scared – that’s the other reason I’ve avoided a career involving strapping lovingly built instruments on top of rockets. The Hubble Space Telescope was first conceived in the late 1970s and launched in 1990, for example. On both sides of the Atlantic planetary scientists are attempting to decide whether the next mission to the outer Solar System will go to Jupiter and the icy oceans of Europa, or to Saturn for Titan’s methane rain and the fountains of Enceledus. Despite the huge efforts being undertaken, I’ve spoken to no one who believes the mission will launch in less than 15 years.

Devoting half of your research life to a project and then having to watch, helpless, as it launches and then plummets through the Martian atmosphere? I’d almost rather be back in my 3rd year quantum physics exam. Almost….

Next time I have a month spare (!) I’m going to spend a large chunk of it going through the HiRISE images. HiRISE is the main camera on Mars Reconnaissance Orbiter, and it produces stunning images of the surface. In fact, the images are so good that if they were of Earth they’d be classified. The detail in each and every one is, as you might imagine, stunning, but one of their latest just knocked me flat. Here it is.

That’s what an avalanche looks like from above. The bright spots on the left are fresh snow, and the fall of snow or ice has kicked up dust over on the right. They’ve even found a before and after image. Like I said, stunning – and think what must be in the other 16.8 TB (yes, TeraBytes) of data that they’ve released.

Update : The entry above was written on the train this morning, and as Bunny pointed out in the comments, I missed an image that is equally stunning. This is what happens when you look home from Mars:

… it’s a rock. Remember the Martian bigfoot from last week?

It seemed that my anger struck a chord, and I’ve been literally deluged with a email asking me to commemorate the fact that it’s a rock. I couldn’t resist marking the momentous discovery of a rock, so you’re welcome to wander over to cafe press and acquire something that will remind everyone you meet…

Emily over at the Planetary Society blog is often full of wisdom, and I’m impressed she managed to keep calmer that I did when faced with ’Bigfoot’ on Mars. (It’s STILL a rock!) She says :

You may find it annoying that after months of virtually ignoring the rover missions, there is finally a much-discussed news story, and it’s on something as silly as a humanoid-shaped rocky outcropping — but please suppress your annoyance and try to use this as a teaching moment.

Well, yes, that’s what I wish the BBC had done, but let’s have another look at that picture. Not the close-up (it’s a rock!), but the panorama. What do you see if you look at it with an astronomer’s eyes? (Sadly, not a planetary geologists eyes, but you can’t have everything).

The first thing I noticed was how dusty the solar panel visible at the front of the picture was (the first clue that the picture was from late in the mission, not from 2004 as was widely reported). Spirit relies on these panels to get the energy it needs to keep itself alive. The Martian nights are cold (too cold for even Bigfoot, I would guess) and without enough energy to heat itself the rover’s electronics will stop working. Dust on the solar panels has always been a good bet for what will kill the rovers eventually; they had some respite when a freak gust of wind cleaned the panels but things are obviously still pretty bad.

Actually, that’s the reason Spirit’s here at all. Mars is tilted on its axis by almost the same amount as the Earth, and so has seasons just as we do. It’s heading toward being winter for Spirit, and that means short days, long nights and little Sun, just as it does for us here in England. Spirit’s driven back to this point, near a place called Home Plate, where it can tilt its dust-encrusted solar panels toward the Sun and hope to wait out the worst of the winter.

Now what about the landscape? There are hills on the horizon, not the Columbia hills Spirit has been exploring as part of its role as the first Martian mountain climber – they’re off to the right – but a reminder that Mars is a world. No matter how much longer Spirit lasts, it’ll never explore these distant features but they’ll be waiting for us.

There are plenty of features nearby to keep us busy in the meantime. The rocks are weathered, I would say, but not by the action of water – this isn’t an old Martian river bed. The weird structures, including Bigfoot (it’s a rock!) are probably the result of erosion by either local or large scale dust storms, like the one that engulfed Mars last year. Sand carried by wind can be quite abrasive – a natural sandpaper, if you like.

Excitingly, many of the rocks seem to have layered structures (see, the close-up is useful for something after all). That suggests to me that they are sedimentary rocks, with each successive band laid down by successive flooding. Even if that’s not true, the presence of layers gives us the prospect of reading these rocks as a history book, working backwards through Mars’ past. If there was ever water in large quantities here, the minerals in these rocks might hold the evidence.

It’s hard for me to forget the bigger picture, too. This is a place, and a view, that Spirit was never meant to see. It travelled long and hard to get here, surviving long past the 90 days it was designed to last. The least we can do is appreciate that the rovers are still working; Emily gets it right once again:

While they’re still there, we should do them the honor of thinking of them every day, checking on the results of their daily toil, because one day all too soon they’ll both fall silent, never to be heard from again..

You can follow the exploits of Spirit and Opportunity at their JPL Home Page, or for the dedicated at Doug Ellison’s excellent Unmanned Spaceflight message board.

Update: I decided the occasion needed marking.

I really believe that the correct way to talk to people about astronomy is to assume that they’re intelligent and interested and move on from there. Yes, explain things simply, but you don’t have to talk as if your audience has the attention span of a stupid goldfish. There are times when I wonder, though.

This started as a joke. The images below, taken by Spirit, are supposed to show a ‘human like’ form.

They don’t. As Rob says it’s a rock. I haven’t had a chance to look at the papers, but I think this was in the Sun this morning. Fair enough – an amusing story. And then I notice it on BBC news online as once of the most emailed articles. BBC News online? Everyone’s favourite internet news source, right? What to expect from them? Perhaps an interesting article using the article as an excuse to write about Spirit’s journey? Or a reflective piece commenting on our human need to see faces everywhere, linking to the excellent Mars Express images of the old face on Mars? Oh no…Here’s their article (currently one of the most emailed) in full with my comments.

BBC : Mystery image of ‘life on Mars’

Chris : There is no mystery. It’s a rock.

BBC : An image of a mysterious shape on the surface of Mars, taken by Nasa spacecraft Spirit, has reignited the debate about life on the Red Planet. A magnified version of the picture, posted on the internet, appears to some to show what resembles a human form among a crop of rocks.

Chris : There is no mystery. It’s a rock. By ‘reignited the debate’ they mean ‘some people on the internet get easily overexcited’.

BBC :While some bloggers have dismissed the image as a trick of light, others say it is evidence of an alien presence.

Chris : Is this supposed to be balanced reporting? It’s a rock.

BBC :The image is a recent Nasa posting of the Spirit’s landing in 2004.

Chris : Is this even English? I think the word ‘site’ is missing. It’s still a rock, though.
Update : The image was taken on sol 1367, more than three (Earth) years after Spirit landed on Mars. So even if it were life and the BBC sent a reporter to do the interview, they’d be in the wrong place.

BBC :When the robotic rover set down on 24 January 2004, its images disappointed space-watchers hoping for signs of extraterrestrial life.

Chris : What? Who are they? Who expected Spirit to take pictures of ‘extraterrestrial life’? This is just rubbish – Spirit is a robot geologist, looking for rocks to study. What’s that you can see in the picture? Yes, a rock!

BBC :Now they appear convinced that this image provides the evidence they have been trawling Nasa’s photo files for.

Chris : I’m glad ‘they’re’ convinced. How many of them are there? Will the BBC be giving them airtime? Do their views outweigh everyone with common sense?

BBC :The blown-up image seems to resemble a figure striding among the Martian rocks.

Chris : As long as the figure is only a couple of centimeters high.

BBC :The internet has been abuzz with postings offering theories. One said it was a garden gnome, another that it was the Virgin Mary. A third suggested Bigfoot, the hairy bipedal mountain beast that appears in various guises in a number of legends around the world.

Chris : And that’s supposed to be good enough to make a news story, is it?

BBC :But the consensus seemed to be that it bore a striking resemblance to the Little Mermaid statue in the Danish capital, Copenhagen. Poster “Madurobob” said it was a statue “obviously built by an ancient civilisation that later departed Mars and settled Denmark”.

Chris : The ‘internet’ as news source. I’m looking forward to tomorrow’s article discussing where Elvis really is.

BBC :Badastronomy.com tried to apply some perspective: “A man? It’s a tiny rock only a few inches high. It’s only a few feet from the rover!”

Chris : And with that, we wake up and realise it was all a bad dream, right? I’m clinging to the hope that what they’re trying to do is write an amusing article, but somehow I doubt it. Every week there is at least one excellent press release from either Spirit and Opportunity, Mars Express or MRO. And this is what makes it onto the front page? Perhaps I’m wrong. Perhaps we get the journalism we deserve. Aggggggghhhhhhhhhhhh…..

Update : Weirdly, it’s not visible in the ‘science and nature’ index at all, although it’s still on the most emailed section. Perhaps they’re ashamed of it?

Today marks the third anniversary (in Earth years) of Spirit‘s landing on the Martian surface. It bears repeating again and again that this is a mission whose design lifetime was 90 days, and yet both Spirit and Opportunity are still going strong, despite dust storms and all that Mars has thrown at them. It’s hard to remember now, but the buzz around the landing was initially negative. The European probe Beagle 2 had just failed to safely land, and so it was with great relief that we all heard of Spirit’s success. The rover suffered software problems almost immediately, and journalists began to scent another NASA failure story. When I was at JPL a while back the press officer escorting us described photographers queuing up to get a picture of the full scale replica of Spirit in the courtyard as it was battered by wind and rain, symbolising the difficulties the real thing was having on Mars. Since then, Spirit has been nothing but a success.

This image is one of my favourites; assembled from Spirit images by the contributors on Doug Ellison’s Unmanned Spaceflight forum, it shows the rover on top of Husband Hill.

To catch up on its amazing story, can I recommend two of the Sky at Night interviews I’m proudest of, both with the rovers’ lead scientist, Steve Squyers? The first is part of our planetary round up from October 2006 and the second is in our Mars special from last February (3 minutes in).

Less seriously, can I recommend this article from the Onion?

If you listened to the latest Living Space podcast you’ll have heard us talking about the then breaking news that a little asteroid called 2007WD5 had a small chance of hitting Mars. At the time the chance was given as 1 in 75, but new observations which have more tightly constrained its orbit raise that to about 1 in 25. OK, as the Bad Astronomer notes that’s still a 96% chance of nothing, but it’s not yet zero.

Given the fleet of spacecraft we have around the red planet right now, this would be an amazing impact to watch; you can even imagine Opportunity seeing the meteor in the sky as it headed for impact, with the crash watched by Mars Express and MRO. It’s a strange shift in perspective; instead of hoping Earth is out of the way, I’m hoping those odds narrow further and January 30th brings a spectacular impact.

Update : Odds now 1 in 28
Update 2 : Mars is safe.