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Wednesday, 25 February 2015

Mass extinctions and darker matters...

Once upon a time, astronomers looked at the rotation rates of galaxies in the universe, and found something odd – the outer parts, which should have been spinning much more slowly than the cores, were spinning almost as fast. Being scientists they, of course, panicked, wept, and ran in circles flapping their hands…… hey, what? I can make fun of them, I am one.

What they actually did was look at the data and start ruling out possible explanations one at a time. Eventually they were left with one: That there was some kind of mass, that telescopes couldn’t see, which had altered the spin rates with its gravity. And they christened it… dark matter.

Because, once in a while, scientists do do cool names.

Above: ESA explains a bit about its hunt for dark matter. No, 'down the back og the sofa'  isn't a possibility

Since then the hunt has been on… and on… and on… and on.. to locate and understand this stuff. But results have been frustratingly hard to come by. The large hadron collider is hunting the stuff, and ESA is building a space telescope, (EUCLID) just to tract the effects of its gravity. Whatever Dark matter really is (and it has an even weirder counterpart called dark energy), it passes through ordinary matter like a ghost, it’s invisible to our senses and instruments, and it outweighs normal matter five to one.

Some scientists have proposed ways in which our understanding of gravity could be off, that would explain what we see without the need for a dark universe. Other scientists are tentatively starting to believe they’ve identified signs of dark matter, and its effects, closer to home…

Dark Matter the killer:
Earth's geological history shows a weird pattern: Every 30,000,000 years or so there’s a mass extinction, as regular as a genocidal cosmic clock. They seem to roughly coincide with times when our solar system passes through the midpoint of the galactic disk, yet the direct causes of the extinctions don’t seem related – a comet strike here, a volcanic mass eruption there.

Above: The green line is the motion of our solar system through the Milky Way galaxy. If you're looking for a reason to feel seasick all the time (I don't know why you would be , but hey, there's 7 billion people on Earth so I'm sure some one is) then here it is.
Professor Michael Ramoino, from New York University, thinks they might all be direct by an unseen force – dark matter. As we pass through he galactic disk out solar system hits an region of denser dark matter, which has two effects: Its gravity disrupts the orbits of comets, causing a lethal barrage of comet strikes. And the dark matter particles themselves are pulled into the Earth’s core by gravity, eventually giving up their energy as heat that warms the core and causes volcanic eruptions - bad for Earth, but perhaps enough to warm the depths of ice covered worlds into oceans?

Dark matter in the Sun:
Back in the present day, some researchers are using dark matter to help explain some strange quirks of how our Sun behaves: The Sun has a complex internal structure, which includes massively explosive events that cause bell like ringing throughout it. This ringing – called acoustic pressure waves – can be measured from Earth, and used to scan the Sun's depths.
Researchers have used multiple sources of data, such how fast these waves travel and how much neutrino radiation the Sun gives off, and have found the mathematical models of the Sun don’t add up. But if the Sun has pulled in a certain amount of dark matter then this can act as a ‘secret passage’ to bring heat out of the core and to other parts of the Sun… and lo and behold with the dark matter in place the models work almost perfectly.

Dark matter signalling

Above: The XMM Newton being readied for launch.Ohhh, shiny. Courtesy of ESA.
The XMM-Newton spacecraft, which we covered a while ago when it launched, produced a strange thing last year: A weak but undeniable spike in the X-ray emission from two of the galaxies it was observing. X-ray spikes at a particular x-ray wavelengths are usually the result of a particular kind of atom emitting that wavelength somewhere along the telescopes line of sight… but this spike corresponds with no known type of atom, no any kind of normal matter predicted by theory. Could this be the elusive signal of dark matter? I have no idea, but there are very clever people trying to figure that out…

Dark energy: Unchanged across cosmic time:
The European Southern Observatory's Very Large telescope has been staring at a distant quasar. By distant I mean 'so far away its light is almost as old as the universe'. That’s kind of the point, in fact – by measuring the spectrum of that light it’s possible to determine if the mass of protons, and the mass of electrons, were the same in the very deep past.

Above: Fraser Cain (not the fictional doctor, that's Frasier Crane) explains quasars.
The verdict? Yes, they were. Why is that important?
This is important because some theories about dark energy (an almost undetectable but very powerful force that is accelerating the expansion of the universe), called quintessence theories, predict the values of those numbers would have been different in the deep past. Any variations have now been ruled out to the 1 in 10 million level, but the search will go on. Julija Bagdonaite, who led the investigation, has said: "finding a variation at, say, the 1 in a billion level would be just as exciting and revealing, and I think that efforts to improve on the current limits will continue".
Above: A quick lowdown on all things dark from Imperial College.

Elsewhere in the universe:

ESA’s successful spaceplane test flight opens the way for improved access to space:
The test flight of the European IXV spaceplane has set the European aerospace community buzzing with ideas for a new generation of space vehicles that would improve regular access to low earth orbit.

Super-bright supernova might be calling card of a new kind of weird object:
Once a star dies it can become any one of a host of bizzare, space and time bending, atom warping, objects. From white dwarfs to black holes, these objects atre the most extreme examples of matter in the unioverse. Now a new one, the theoretically predicted quark star, may have been spotted.

Elsewhere on the internet:

New images of CERES - possible volcanoes?

Hubble does survey of KBO’s

Asteroid redirection mission gets some love

Massive explosion on far side of Sun

Sunday, 22 February 2015

100 years of asteroid strikes....

100(ish) years of asteroid strikes:
If a rock hits you on the head the natural assumption is... someone threw it, the house is collapsing, a malicious hang glider dropped it.....well anything other than 'it dropped out of an empty sky'.

Because the world doesn't work that way... except when it does.

In fact the main reason people don't get scares like that more often is just that it's a big ass planet Earth. Lots of it is uninhabited (or the ocean), and most people  spend most of their time inside. The University of Western Ontario did a study of US early warning satellite readings over eight years. He identified 300 explosions caused by 1 to 10 m  sized space rocks in that time. It happens a lot: below is a map of all the asteroid impacts over 9 years

The 'Little Boy' Hiroshima bomb would fall in between the second and third blobs on the right hand end of the scale - that's a lot of bang, but look how much falls over the ocean, or sparsely inhabited areas - it's no wonder most go unnoticed.
The reason why we don't all live in concrete and steel underground shelters is our planet's atmosphere, that heats most of them so much they explode well above ground height - without it this would happen fairly often:

OK, an asteroid that size would get through anyway. Somehow I never get tired of seeing CGI cities bite it....

...but bare in mind that (outside of Cameron land) that's a one in 10,000 year event, so  please don't make like the citizens of Springfield.
Little fragments that do make it to the ground are much more interesting than dangerous - they're literally fragments of ancient worlds that died long ago, bits of protoplanets, not to mention bits of comets, and remnants of the solar nebula that the solar system grew from. But even a small rock can be spectacular, so here are some of the most significant impacts of the last century (ish):

Great daylight fireball, 1972:
I grew up with this one on screens and in pictures a lot - I'm a child of the 80's, and this was one of the first daylight-bright events to be captured on camera. It's thought to have been about three meters across, and travelling about 15 km per second - look at how it moves against the back ground clouds, and remember it's still over 50km up. The sheer speed is gobsmacking. It could have announced itself by finishing with a nuclear bomb sized explosion, but it after about a minute and a half this visitor skipped off the atmosphere and back into space.

Comet Shoemaker Levy 9, 1994:
Yes, I know, but I never said just impacts on Earth. Shoemaker-Levey 9 versus Jupiter was a great example of how gravity takes no prisoners:  The comet was torn into a string of chunks by the gravity of the greatest giant planet, which were sucked down to their doom on the next orbit. Jupiter didn't get off un-bloodied though, as the impacting comet fragments became fireballs thousands of kilometres across, leaving clouds of debris bigger than Earth in the atmosphere for weeks afterwar4ds.

Carancas, 2007:
The Carancas strike in Peru was a rare example of an object getting to the ground intact enough to do some real harm:

Above: The crater at Carancas, Peru..Courtesy of The Meteorite Guy (that's him)
This was big, hard iron, meteorite - a fragment of the once molten core of some ancient protoplanet -  and it punched through the atmosphere and hit the ground still hot from re-entry. The physical blast knocked people in the nearby village over, and damaged houses. But the worst effect was on the  ground water around the impact site - it boiled, and the ground contained arsenic compounds, which were spread with the vapour droplets. Locals went to see what happened, and hundreds of people who got near to the crater fell sick. Police arriving to investigate the scene also fell ill. The number of people falling ill increased as the vapour spread, suffering were treated for skin injuries, nausea, headaches, diarrhoea and vomiting. Livestock in nearby fields died, and authorities considered declaring a state of emergency. Luckily no-one received a fatal dose, and four days after the meteorite impact  most villagers reported had recovered

Above: A fragment of the Carancs asteroid, showing the triangular Widmanst├Ątten crystal pattern found in iron meteorites. Courtesy of the national museum
Nameless space rock hits the Moon:
The  Moon doesn't have much of an atmosphere, so anything coming in with out a retro rocket hits hard. The tiny flash of light in this video would be a terrifying, lethal, blast if you were up close -  it shows up on a world sized image, after all. A wandering space rock found the unyielding lunar rock in its path, and in an instant its kinetic energy -  tens of kilometres per second worth - became heat and blast.

Wabar 1863/1891:
The tribes in desolate corner of Saudi Arabia told stories about something massive and bright that tore through the sky over their tents. When an expedition went to the area the object seemed to have come down in - an expedition actually searching for the lost city of Ubar (pronounced Wabar) - they found craters, the biggest of which was over a hundred meters across. Sand had been melted to glass by the heat, and fragments of nickel iron meteorite were mixed into it, producing the dark 'Wabar glass' that litters that part of the desert.

Above: The rim of one of the biggest craters. If there was a derelict city on this spot... there isn't one now...

Above: A fragment of meteoric iron recovered from the Wabar crater, with  the Widmanst├Ątten crystal pattern.

Tunguska, 1908:
In 1908 something came down over the forests of Siberia, in the Tunguska region. What the villagers of the area described sounded incomprehensible - a massive, unbearably bright light, an immense cloud of dust, and a roaring wind. Thousands of square kilometres of forest were flattened by an incomprehensible force: Trees flattened, branches blow off, laying in a titanic radial pattern - in the centre the trees had just been blasted straight down into the dirt. But there was no crater, and no fragments conclusively from an asteroid or comet were ever found. Had it hit a city, million would have died. A mystery like this needs a better mind than mine - so I'll hand you over to the legendary Carl Sagan:

Above: Ladies and gentlemen, I give you Carl Sagan.

Above: A computer simulation of one possible Tunguska fireball, courtesy of Sandia Labs.

Ann Hodges 1954:
Sometimes the universe gets personal. This must've been how Ann Hodges felt when a meteorite smashed through the roof of her house, bounced off of her radio, and hit her squarely in the hip. Bruised, but otherwise alright, she became famous overnight, as the first definite case of a person being inured by a space rock

Above: Ann shortly after she was hit (left), and many years later holding the space rock responsible (right0 
The Almahata Sitta meteorite, 2008:
This was an 80 ton space rock that blew up harmlessly over the Nubian desert in 2008. What was remarkable was that this was the first ever object to be detected (by the Catalina Sky Survey) before it hit.

Above: An infra red satellite image of the meteorite blowing up over the desert.

Around 600 chunks were recovered, and turned out to be of a rare kind called ureillites.
It contained a lot of oddities, including nanodiamonds, and molecules from life-like chemistry, known as amino acids.

South Africa 2009:
South Africa got a visitor from space, and although not much was found of this one it's a good example of how mre and more impacts are being caught on cameras, worldwide:

Chelabisnk (Russia again), 2003:
If you missed hearing about this one... you must have been under the bed. For two years. But clearly you have internet there, so you should still know: By asteroid standards this was a fairly mild demonstration  of power, but, still, the numbers are impressive: The 20 meter wide rock hit the atmosphere at nearly 70,000 kilometres an hour. It exploded twenty kilometres up, with the force of twenty Hiroshima bombs, and the fireball was brighter than the Sun even a hundred kilometres away. The blast wave triggered a magnitude 2.7 earthquake. And it was right over the city of Chelabinsk - thousands of people were injured, thousands of buildings damaged. And, by asteroid standards, this was still a tiny one.


Elsewhere in the universe:
Would you live out your life on Mars? These folk would, and might, might,  get the chance to do so.

Fall into a black hole:
The BBC gives a nice explanation of what happens to things falling into a black hole.... yes they end up very dead and crushed, but there's details that are interesting:

Elsewhere on the internet:

Why the Sun is actually green

MAVEN mission dips into the Martian atmosphere

Sun gives out polar jets

Dark matter turns lethal

Solar storm and Earth's magnetic field conspire to accelerate particles to incredible speeeds

Thursday, 19 February 2015

Did we have visitors?

Above: Proxima Centauri, the nearest star to us.. for the moment. Courtesy of
Our solar system has a very, very long history, and it's not even the oldest solar system like ours around - that honour goes to Kepler 444, a Sun-like-star system that is a staggering 11 billion years young. We've never found convincing evidence of any kind of life beyond Earth (that we didn't put there). But space teems with the kind of molecules and chemistry that go into making life, and the jury is very much out on whether or our kind of chemistry is the only kind that could support life -  just look at the chemical imbalances discovered on Titan or Venus, imbalances that might be the result of very alien kinds life. On top of this a recent result from SETI listed 1072 signals from deep space that were 'statistically significant' - or, put another way, unusual enough to warrant following up with more investigation.

Of course following those signals might have a down side...

It's a very long way to the nearest star system, Proxima centauri, though - and that solar system isn't even looing very promising for habitable worlds.

Interstellar on the cheap(ish):
There is a recent find that might change the odds of our solar system getting an alien visitor. This week a paper was published describing how, 70,000, years ago another star passed within less that a light year of Earth. We know it as Scholz's star, and it came within the outer boundaries of the Oort cloud, our solar system's cloud of comets.  Encounters like this might happen on a fairly regular basis according to Dr Mamajek,  who helped discover the star's flyby. Although previou simulations suggested these close encounters happen only once in 9,000,000 years, he believes it's likely a small dim star like this probably passes close every hundred thpusand years or so:
...It is a bit of a strange coincidence that we happen to have caught one that passed so close within the past 100,000 years or so.

- Dr Mamajek, speaking to the BBC

Could a similar encounter in the deep past, a flyby by a star with an inhabited world,  have left the relic of someone else's exploration effort hanging above our skies?

No, we'd notice one of those. I'm almost sure 
If a star with a habitable world passed so close by today then our fastest spacecraft, New Horizons,  would take 16,000 years to make the trip. The fastest proposed space craft that'd use current tech, the Innovative Interstellar Explorer, would need 6000 years. The fastest proposed spacecraft that'd use technology we could realistically build today, the TAU (Thousand Astronomical Units) space probe, would need 2500 years. We would need a spacecraft 25 times faster than TAU to make the trip in under a century.
That sounds un-promising, but the gap between humans reaching New Horizons top speed and the Wright brothers top speed was only a century of technological development. People have undertaken projects over many lifetimes often enough in the past, like York Minster Cathedral, and space agencies are developing new engines all the time - take the NEXT or VASIMIR space drives , which are currently undergoing testing.
We don't know how an alien race's technological history might play out - they could develop fast and not need a close stellar encounter to make the trip - but they'd still find it easier. Or they might hit a technological plateau at some point. In either case, a star that was very near to their own at some point in their history would surely get more attention; even for a very advanced civilization interstellar travel (using physics we understand today) would still be a huge undertaking, and consume massive amounts of energy.

Looked at like that, the idea of a civilisation just a little more advanced than us, making the trip in the distant past when our solar system happened to be exceptionally close, seems worth considering. But would we be able to tell?

A probe that simply did a fast flyby without stopping wouldn't have left any trace. But a probe that went into high orbit about one of the solar system's worlds, or the Sun, could remain here for millions of years. Our solar system is 4,500,000,000 years old - so if Dr Mamajek is right there have been 45,000 close encounters where a probe could have made an easier crossing. What's more, some researchers believe that 'mail'  might be the best way for an alien probe to communicate, which entails a physical messenger we could observe moving back and forth.

Yoda lived to 900, patient little alien is he.
Alien space probe?
Have we ever seen something that could fit the M.O. of an alien probe? Probably not.. um.. here's the abstract for a paper by Duncan Steele, describing a strange little object that seems to have been following Earth (here's a link to the paper) 
Abstract: A ~ 10-metre object on a heliocentric orbit, now catalogued as 1991 VG, made a close approach to the Earth in 1991 December, and was discovered a month before perigee with the Spacewatch telescope at Kitt Peak. Its very Earth-like orbit and observations of rapid brightness fluctuations argue for it being an artificial body rather than an asteroid. None of the handful of man-made rocket bodies left in heliocentric orbits during the space age have purely gravitational orbits returning to the Earth at that time, and in any case the a priori probability of discovery for 1991 VG was very small, of order one in 100,000 per anmun. In addition, the small perigee distance observed might be interpreted as an indicator of a controlled rather than a random encounter with the Earth, and thus it might be argued that 1991 VG is a candidate as an alien probe observed in the vicinity of our planet.
Since then some of the unusual aspects of 1991VG have been explained, but not all. And, although an extra-terrestrial probe is not likely, it does opened a path of thought on the subject: Look at our own currently advancing trends of miniaturisation and we can wonder: How small, and how hard to find , might an alien probe loitering in our solar system be?

The answer seems to be 'very' - we ourselves have fist sized space craft called cubesats. Fingernail sized chipsats, which are touted as a technology that could get to interstellar speeds, are being developed. If anything 1991 VG is too big, and too obvious to fit the bill.

Above: A Cubesat spacecraft being built. Courtesy of M.I.T.
It may be that we will never know, but if one day we stumble across something.... well, given the 4.5 billion years our solar system has had to be visited in, perhaps we shouldn't be surprised...

Elsewhere in the Universe:

The New Horizons probe has captured its first views of Pluto, and it's absurdly big moon Charon. You can see here that Charon is so big it and Pluto orbit about a point in the space between them (called a barycentre)

The DAWN mission has captured its best view yet of the dwarf planet Ceres - and the clever folk over at have managed to match dawns black and white images with lower resolution colour shots taken by Hubble, to produce coloured versions.

Above: Ceres in (exaggerated) colour. Courtesy of Phil Stooke and Ian R.
What's amazing is how closely the images match. We're already seeing structure and shape to the white spots littering one hemisphere, and we're starting to see things like pancake shaped plateaus, long chains of mountains and gigantic slopes stretching over hundreds of kilometres. Phil nStooke has also created this animation, based on the best images to date:

News from the Moon: As if in response to the last few weeks' moon theme, the latest data from the Chang'e lunar mission has arrived! Here and here.

Elsewhere on the internet:

Cubesats come of age?

Micro spacecraft to explore Jupiter?

Strange clouds on Mars

Why comets are like fried ice cream with chocolate?

Monday, 16 February 2015

I simply couldn't pass this up...

I'll be honest, I picked this one because it looks cool
I do have a solid post planned for later in the week, about some of the recent, and spectacular, meteorite impacts that have happened here on Earth.

But I'd have to hand in my nerd card if I didn't share this video. It's from a spacecraft called the Solar Dynamics Observatory, which holds a position in space and watches out Sun across a wide range of the spectrum. I - in avery small way - try to support solar exploration, by submitting my own amateure Sun observations to the AAVSO's solar observers section. But this is what the best tech of the world sees of the Sun: A living, churning star...

Sunday, 15 February 2015

The invisible world part 3: The eighth continent

Sometimes our Moon is called 'the eighth continent'*: The Moon is so close to Earth, and so intertwined with Earth, that the two worlds can't truly be considered separate...

Above: Earth and Moon, side by side in space. It's a big cold universe, and event worlds need to stick together in it... Courtesy of ESA.

What can mankind make of our eighth continent?
There're lots of plans for far into the future: Proposals for manned lunar bases abound - it's practically a hobby for lunar scientists - but a lot will depend of getting to know the stores of water ice, rare earth metals, organic compounds, and other resources better. The ideas put forward include solar panel energy farms, robotically built radio telescopes on the far side, adventure tourist expeditions and sample return missions from the poles.

There're less ambitious ideas as well: Space Adventures inc intends to launch a privately funded manned lunar mission, and NASA intends to test its Orion space capsule by doing a loop around the Moon. NASA also plans to give the Moon it's own moon, by capturing a small asteroid and towing it into lunar orbit

Above: NASA's plan to kidnap a space rock. Which may well morph into a Moon landing or something when a new president comes in, but that'd be cool to, it's space! Courtesy of NASA.

We've seen that it's a world worth exploring in its own right. Aside from everything I've mentioned in the last few weeks, there're still many mystery's I don't have time to cover, like the water-altered minerals found by Apollo 16 (very odd at the bone dry equator of the Moon), or the way that cosmic rays hitting organic chemicals in lunar ice produce 'pre-biological' molecules of great complexity. There's still a lot to learn, so, even though you won't be buying a lunar bungalow for a while, in the nearer term we can expect more robotic missions.

Some of the most interesting are the Lunar X-prize missions. The Lunar X-prize is an initiative by Google to encourage interest in lunar exploration: 20 million USD to the first team to land a small robot on the lunar surface, travel 500 meters and send back pictures and video.
This could be a start of a sea change in how we use (or don't use) the Moon. If nothing else it has already inspired a lot of interest in the kind of lunar science and engineering that could be done privately. The Moon was once for mega funded government organisations and right stuff astronauts, but over the last fifteen years space agencies with less staggering budgets and have begun exploring the Moon. Now there are eighteen private teams, with the frontrunners looking to launch in the next eighteen months: 

Above: A quick chat with the teams. Well, I say quick. I don't actually mean it. An hours chat with the teams.... make a cuppa. Courtesy of Google

The Barcelona Moon Team GXLP mission is scheduled to launch aboard a Chinese Long March 2C in June 2015: 

Above: The Barcelona team explain some of their strategy

Moon Express isn't mucking around with the small stuff: As well as being lunar X prize competitors they've signed contract with NASA to sell data from their mission (scheduled to launch in 2015) worth $10,0000,000, and plan to set up lunar radio telescopes by the end of this decade. On June 30, 2011, Moon Express had its first successful test flight of a prototype lunar lander system called the Lander Test Vehicle (LTV), and have been progressing since then:  

Above: A Moon Express lander test.

Bob Richards, the company's founder, doesn't want this lunar landing to be a one-off experience: "The founders of Moon Express believe in the value of the moon and its resources..... In the long term, we're looking to develop, basically, a railway to open up the possibility of lunar resources complementing our economy here on Earth, expanding our economic sphere out to the moon."

Astrobotic are equally ambitious, with a launch date set for their Polaris rover in October 2015, and eyes on the dream of launching a Mars mission in the future. Their Griffin lander is set to launch in 2016, with a rover called 'Andy' from the Carnegie Mellon University aboared - the destination is a lava tube, something that has never been seen up close before. The plan to begin a private 'lunar delivery service' for payloads. 

Above: An Astrobotic flight test

Thornton and representatives for Astrobotic see the X Prize as a way to kick-start a lunar industry.
"We'd be perfectly happy landing on the moon and placing last in the X Prize," Astrobotic funder Thornton said. "That would be fine by us. For us, the big win is to commercially land on the moon, and open up the pathway to the moon." And Astrobotic have put their money where their mouth is by offering to help arrange one rocket launch to carry all the competing missions to the Moon.

At the other end of the spectrum, SpaceIL are a tiny Israeli company, whose Moon shot is as much about inspiring the next generation of scientists and engineers as landing on the moon itself: "Today, when we look at it, our mission is to land the first Israeli spacecraft on the moon," Damari said. "Our vision is much, much bigger. It's to inspire the next generation of scientists and engineers: 

Above: SpaceIL on the trajectory their mission will take

The won't even be the first private mission to aim at the Moon: The Manfred memorial lunar mission performed a flyby of the Moon earlier this year, and the British mission (called, um, Lunar Mission One because we're British) has achieved its kickstarter funding to begin developing their lander, which will drill into the surface of the Moon looking for clues as to its origin and history.

That doesn't mean the old school space agencies are idle: China has landed its Change 3 mission, consisting of a lunar lander (which doubles as a science station and lunar observatory) and its Yutu rover. NASA has the LRO orbiter, which seems to uncover new answers and more questions about the Moon daily. More missions are planned with China's Change 5 sample return mission making good progress towards launch, and India's Chandryaaan 2 also steaming ahead. ESA is looking to the Moon as well, as a place for co-operative ventures:

Above: ESA's ideas for how our use of the Moon might evolve. It's  place you can have a view of everybody's house. SO that's the French in at least...

What I find most intriguing are a lot of  the small mission proposals - they're varied and sometimes strange. Here're a few that've caught my eye while I wander the net:

The Nanoswarm mission proses using a fleet of cubestats (fist sized minature spacecraft used for low cost missions) to explore the Moon's water, magnetism, space weathering, and magnetic anomalies  .

The Naaki mission plans to study the lunar cratering rate.

There're ideas for miniature landers, and for cubesats diverting sunlight onto the poles to locate ice deposits. There're a lot of ideas, but now there're also lot of people building craft, and booking launches to. The Moon seems to be a place with a future in private exploration: NASA has been running its lunar CATALYST program  - intended to advance and encourage private lunar exploration -for over a year now, and has selected Astrobotic Technology Inc., Masten Space Systems Inc. and Moon Express Inc. to receive technical assistance and support to land cargo on the lunar surface.

Perhaps this is all humanity's next step into the wider solar system. Perhaps not. But it'll be interesting to find out.....

Elsewhere in the universe:

I could hardly not mention this stunning image from this weeks successful SpaceX laucnh, which carried the DSCOVR deep space environment mission into interplanetary space:

Above: This view was taken from the rear of the SpaceX rocket, as it pushes the DSCOVR space platform into it's orbit around the Sun. The rocket seems to be looking back and saying: That's it, I'm out of here... a big black sky awaits me.  Courtesy of space X

Space X also had a good test of their technologies for recovering a spent launch stage, landing within ten meters of their target, with the rocket upright and fully controlled - only stormy weather prevented the rocket being recovered and potentially reused.

Elsewhere on the internet:

Survey of NEO's and meteorites

Martian Moon Phobos has water and water altered minerals?

Planck space telescope constrains cosmic inflation

Sharpest images yet of Titan reveal strange landscape more clearly

* Admittedly it also gets called ' that blasted chunk of shiny c**p by astronomers, when it gets in the way

Wednesday, 11 February 2015

Enceladus: The moon with the soda lake ocean....

Above: The big, organic chemical shrouded, moon Titan is the backdrop for teensy moon Enceladus, and a section of the rings of Saturn.. By Teensy I mean 500km across. That's teensy, as moons go. Don't go making them feel bad about their colossal girth. Courtesy of NASA.
The distant Saturn system - one gas giant, innumerable moons, and rings - has mysteries aplenty. Luckily we've had the Cassini mission exploring this incredible part of the Universe, and it has discovered two worlds there of particular interest: Titan, with its bizzare 'cryogenic Earth' environment, and Enceladus, a tiny ice ball, with an inexplicable heat source at its southern pole, keeping a tiny ocean warm....

...and now we know a little more about it. This isn't just a pond of meltwater - using data from Cassini Christopher Glein, John Baross, Hunter Waite have found that, as well as being loaded with salts and organic molecules, the water is strongly alkaline like the soda lakes of Earth.

Above: A Hippo at a soda lake in Africa. The sea of Enceladus is like this, but under miles of ice, billions of miles away in space, and without the hippo.
I'm not 100% on the hippo, but it's not likely anyway..... courtesy fo Wilds of Africa.
Even though the PH is strong (11 to 12) this isn't bad news for those hoping to find life beneath the ice one day. Alkaline lakes with the same PH are usually full of unique organisms that have adapted to the waters. We can also use this to infer some things about Enceladus core and heat source - for example that its core has probably never differentiated into inner and outer parts.

Elsewhere in the 'verse:

NASA have released a video showing the far side of the Moon, using data from the Lunar Reconnaissance Orbiter Mission:

This week the LRO team have also announced that hydrogen at the Moon's poles (some of which is thought to be bound up in water) seems to be slightly more abundant on the poleward facing slopes.

ESA had a successful first flight for it's Intermediate eXperimental Vehicle (IXV) spaceplane. The design isn't meant for development into a full line of ships, it's a stepping stone to something like a civilian version of the US air force's X37-B unmanned spaceplane in a few years.

Above: The Launch of the IXV. Courtesy of ESA.

Elsewhere on the internet:

Number of asteroids reachable by spacecraft doubles

Bacteria turn sunlight into car fuel.

Plank space mission reveals a map of our baby universe

Europe's ATV spacecraft meets a fiery end.

Asteroids underwent 'nonlinear' cooling

DARPA will begin testing an innovative scheme to lower the cost of small satellite launches

SpaceX has second attempt at re-usable rocket test

Sunday, 8 February 2015

'The invisible world part 2: The Moon today'

Above: The Fallen Astronaut, a monument on the Moon to all the astronauts and cosmonauts who have lost their lives. Courtesy of NASA

My Dad's a geologist, so I know that the dullest rock has a story to tell -  and the Moon is big rock, with a big, old, story. But it's also more than that: We're uncovering a subtle but complex modern day Moon. A world with mountains of eternal light, valleys of perpetual darkness, gas explosions, buried ice, delicate frosts, unknown mists, mysterious magnetised swirls, tunnels miles wide, and historic monuments....

An active Moon?
For a long time the Moon was assumed to be essentially dead, but we now know a lot of things are happening there... 

Moon quakes:
Above: The Moon is occasionally hit by larger meteorites, travelling at incredible speeds, but they don't come down often enough to cause all the quakes that are observed.

When the Apollo missions visited the Moon they left behind science stations that monitored the Moon for seismic activity. These stations were active on the Moon until 1977, when they were closed down by budget cuts. They found  that the Moon often experienced quakes, up to 5.5 on the Richter scale - enough to damage a building if it isn't well constructed. Deep quakes are probably caused by the  tidal gravitational stress the Earth puts the Moon under. But the origin of the shallow quakes is still unknown, and while they don't get as strong as Earth's strongest quakes they can last for up to ten times as long, setting the whole Moon ringing like a bell. 

Above, Buzz Aldrin sets up one of the lunar monitoring stations, proving that you can travel to another world and still wind up having to put together the equivalent of Ikea furniture. Courtesy of NASA

Active volcanoes:
The Moon has volcanoes, but for most of my lifetime it has been taken as 'obvious' that they must have all gone extinct over a billion years ago. When amateur astronomers reported seeing eruptive activity, the consensus from the scientific community was to lump them into the same group of people who believed “the face on Mars” was a sign of intelligent life.

In case that means you, I'm sorry to have to tell you that the scientific community thinks you're nuts. But take heart, it turns out the lunar eruption theorists at least had a point.....

There was one puzzling volcanic region called Ina D which, geologists admitted, might be a result of younger eruptions,  but generally the Moon was dead.... until spacecraft like LRO and Clementine got there, and began taking high resolution images of the surface. It turns out it's quite possible the Moon is still active...
Above: The Ina-D formation, which is thought to be the collapsed vent of a very low sloping volcano, mainly because the idea of an athletes foot that big is just terrifying.. Courtesy of NASA

Scientists studying these images over the last ten years have revealed tell tale signs that there's still some heat and power left in the Moon. There're seventy more features like Ina, where: 
  • Lava flows are much less worn down by meteorite impacts. 
  • The ground has accumulated few large craters. 
  • Rocks are a subtly (but measurably) different colour
All of which suggests these rocks were formed within the last ten million years - an eye blink geologically, and so recent it seems almost certain there'll be future eruptions.

Above: The locations of some of the young volcanic formations on the lunar surface. Courtesy of NASA

Above: An exaggerated colour image of the Ina formation and a fresh crater, showing how the younger material is bluer in tone. Courtesy of NASA

While the lava eruptions are geologically young, there's also some evidence that gas eruptions might even be on going today: Areas like Ina show evidence of being swept clear of dust by gas eruptions, maybe even in the last century. And, ever since the invention of the telescope, certain parts of the Moon have shown mysterious glows 'mists' - like something was stirring up the dust.

Above: Schroter Valley, sometimes called 'the most haunted place on the Moon' for all the unexplained lights seen there. Courtesy of ESA 

Lunar weather?

Talking about weather on a world with no atmosphere seems odd, but there are some surprising lunar equivalents of weather on Earth, like...

Moving  dust:
The lunar dust moves around on the lunar surface, driven by static charges rather than the wind - UV light and charged particles from the sun cause static charges to build up on the surface. The lunar dust is pulled between regions of different charge in the same way this kids hair is being pulled towards the balloon...

This phenomena was first picked up by experiments left on the Moon by the Apollo missions, and might be a cause for the mysterious glows seen over the lunar surface by some spacecraft. Lunar dust might even be 'blown' vast distances across the lunar surface by these charges, and dust from meteorite impacts can also pick up charges, forming a tail of levitating dust behind the Moon. The LADEE mission is currently at the Moon, investigating exactly this. 

Above: A quick rundown, courtesy of NASA, of the LADEE mission.

Seasonal frost:
Above: A frost flower, which forms when water vapour freezes onto a growing collection of water ice, without going through the liquid phase. Is it possible the Moon has something similar?

The Moon's poles hold craters and valleys where the sun literally never rises, and where the temperatures are so low that water frost can build up even in the lunar vacuum. But these regions are not entirely lightless - the sunlight can reflect off of surrounding mountains at angles that vary during the year, so the frosts can migrate across the valley floors, following the regions of deepest shadow.

Landslides and gullies:
Some of the best evidence for the Moon as an active, changing, world is simply that the landscape visibly changes between photographs taken a few years apart. Recently, comparisons between younger and older photographs have shown us that landslides are constantly sculpting and reshaping the Moon's slopes in response to impacts and quakes, making the lunar surface a constantly evolving thing.

Mysteries of the Moon;

Lava tubes:
Above: The collapsed roof of a lava tube allows an orbiting spacecraft to peek inside

Lava can carve out - or perhaps more accurately grow - underground tunnels called lava tubes. On the Moon we've had glimpses of these, where the ceilings have collapsed. Some of these are a mile across, giving the Moon a network of titanic underground tunnels - what's in there, we may never know.... 

Above: Since I couldn't arrange a tour of a lunar lava tube, here's Tony Farley taking us through one on Earth. Just imagine everything a lot bigger, and everyone wearing space suits...

Permanently shadowed regions:
Above: A temperature map of the lunar poles, showing regions where the temperature is cold enough to hold ice.

A lot has been written about the permanently shadowed regions at the Moon's poles, but for those who've not heard of them: The Moon has craters at its north and south poles so deep that the Sun never shines directly into them - they're colder than the back side of Pluto, on the far edge of the solar system. For a long time it was theorised that ice and other low temperature materials might have accumulated there, but it was only since the late '90's that solid evidence began to build for ices there. The LCROSS mission revealed not only water ice but organic materials, potentially making the poles a time capsule for the earliest organic chemistry in the solar system, and a laboratory for how organic chemistry behaves at low temperatures.

Thorium anomaly:
There's a patch on the far side of the Moon that just screams 'odd'. It's called the Compton-Belkovich Thorium anomaly. It has a high concentration of the radioactive element thorium, has a quartz rich highly reflective soils,  and seems to have been a volcanic hotspot - one of the last really big volcanic regions on the Moon to stop erupting. With a central caldera it might be the Lunar equivalent of a super volcano like Yellowstone.

Why is the lunar crust thicker on one side?
One really basic mystery on the Moon is that its crust is thicker on one side than the other. A lot of explanations for this have been put forward, including one I mentioned last week -  that there was once a second, smaller Moon. The smaller Moon hit the bigger one at a slow speed, and ended up pancaked over one hemisphere like a huge bug on an even huger windscreen... but we just don't know.

Where does lunar water come from?
When the existence of lunar water came to light it was something of a shock to a lot of scientists, and it's origin still hasn't been nailed down - it seems to be created by a chemical reaction with the lunar rocks, but some could also come from cometary impacts, and there even seems to be some water coming from inside the Moon....

Treasures from the Moon

Some things on the Moon are just plain beautiful, so here are few of the Moons treasures:

Beads of volcanic glass:

Sunrise over Tycho:

The Earthrise:

Lunar swirls:
These mysterious waves of colour seem to be etched into the lunar surface. No-one knows how they form, although they all have magnetic anomalies associated with them.

Above: No, it wasn't a kid with a spray can. That'd be some ambitious graffiti though... Courtesy of NASA.

Next Week: Will the Moon become Earth's Eighth continent?
This view of the Moon rising, from the international space station, hints at what the future might hold... 

Elsewhere on the internet:

Superfast octopus robot.

Most stars have Earth-like planets?

'Dark matter galaxy' found

Space X to launch mission to study deep space environments.

Spectacular new map of our galaxy.