NASA captures a new 3D view of Mars’s moon Phobos

NASA You’d think that Mars’s moon Phobos – a 13.5-mile wide lump of brownish rock full of craters – wouldn’t be the most interesting place in the Solar System to take photos. But then space exploration does tend to throw up a lot of surprises.

One of NASA’s Mars probes recently captured the above image, and it’s revealing some fascinating details about something most people probably didn’t even know existed.

The most obvious thing about Phobos is the huge crater on the bottom-right of the image. Scientists say that its slight bluish color means it hasn’t been exposed to space as long as the rest of the moon, meaning the impact that produced the crater could have been quite recent.

Wikipedia Phobos may also be home to water-ice and materials rich in carbon, which is why a Russian-Chinese mission to collect samples from Phobos is expected to launch next summer.

NASA’s Mars Reconnaissance Orbiter snapped the new shot of Phobos from 4000 miles away, so I’m pretty impressed that the detail’s so good. In the full size image each pixel represents 22 feet (6.8 meters), so you can zoom in quite a lot. (Click here to download the full-size image. Be warned! It’s a 20mb file, so if you’re still using ancient dial-up be prepared to wait a few hours.) It’s really cool zooming in on the thousands of craters dotting the moon, especially the ones on the edge of the Moon and on the day-night border.

Phobos and Deimos What else is so great about the new image? OK, several probes have imaged Phobos before, but because MRO took two photos you can actually see the photo in 3D if you’ve got some of those special glasses.

The image also shows landslides around the massive crater (Stickney crater), and you can see some craters in the dark region illuminated by Mars-shine. This is when light from the Sun reflects off Mars onto Phobos, and it happens with the Earth and our Moon too – take a look next time there’s a crescent Moon.

Above all, I just think it’s amazing that yet another bit our Universe is proving to be so interesting. Before I heard about this photo I just though Phobos was a boring old lump of rock, but as you can see it’s actually a pretty interesting corner of our Solar System after all.

Want to know more about the Red Planet? See the Solar System’s biggest volcano in 3D, see photos of the first ever avalanche captured on Mars, and read why radiation may prevent humans from ever visiting it.


Replica Solar System discovered 5,000 light years away

BBC News

Back in ancient times most people thought that our planet was at the center of the Universe. Then we thought it was the Sun, and not too long after we realized that we’re actually just a tiny part of one of billions of galaxies in a Universe filled with trillions of other stars. Just over a decade ago one of the last things that we thought might be unique about our Solar System was disproved – the first ever planet outside our Solar System (an ‘exoplanet’ for short) was discovered around another Sun.

Wikipedia Now our uniqueness has been eroded away a little bit more – a British team of astronomers has discovered what looks a bit like a replica of our own Solar System, orbiting around a star 5000 light-years away.

OK, it’s not an exact replica, but the resemblance is quite striking. Two giant gassy planets (like Jupiter and Saturn in our own Solar System) have the same mass ratio to their sun as Jupiter and Saturn have to our own Sun. And the size of their orbit is proportionally the same as the orbits of Jupiter and Saturn. (The star in the newly discovered system is only about half the size of our Sun, hence the reason why all the figures are given as ratios). The orbital period of the giants is about the same too.

So what about a copy of Earth and the other inner, rocky planets? Well, the scientists didn’t actually discover a new Earth, but they say that the existence of an Earth-like planet is quite likely because there is plenty of empty space in between the gas giants and the star.

Wikipedia Unfortunately there’s not much chance of us discovering any more planets in this system – at least not yet, anyway. Current techniques simply aren’t powerful enough to see such small objects so far away.

But wait a minute… if the system’s so far away, how could we detect that the giant gas planets were there? They’re pretty tiny too, surely, compared to the size of their sun?

They used a clever trick called ‘gravitational lensing’, which involves the effect first predicted by Einstein that if you put a heavy object (like a star) in front of another object (like another star further away), the star in front will bend the light from the star behind because gravity bends light. This enables us to see faraway objects much bigger than we would usually be able to see them. (Click here to read more about gravitational lensing, and how it enabled the Hubble Space Telescope to see a galaxy 13 billion light years away.)

Since we don’t know for definite that there’s a replica Earth in this system, should we really be getting so excited? I think the answer should definitely be yes – in the decade since we first discovered extrasolar planets, 300 planets outside our Solar System have been discovered. The more variation among these planets, the more chance of eventually finding ET. And that would be seriously cool.

Click here for NASA’s excellent exoplanet website: PlanetQuest.

The youngest planet ever discovered – only a few hundred years old A few hundred years is a huge length of time for humans, but in cosmic terms it’s absolutely tiny. A hundred years in the world of Space could easily be compared to a millisecond for humans. But now scientists have discovered a planet that may have formed in as little as a few hundred years – which beats the former fastest forming planet by about 10 million years.

OK, it hasn’t finished growing yet, but the fact that it can be classified as a planet when it’s only been around for so little time is amazing astronomers all over the world. And the planet’s not the only interesting thing – its sun has only been around for a few hundred thousand years. (By the way, the planet and its sun are around 520 light years from Earth.)

So if this planet’s so young, how did astronomers find it? They used the Very Large Array (VLA) in Arizona to search for wavelengths of radiation that corresponded with pebble-sized lumps of rock (different sizes of rock emit different amounts of heat). They looked for pebbles because they are a vital hint that a planet is being formed.

National GeographicIt may be an intriguing discovery, but does is actually mean anything in terms of knowing more about our Universe? It certainly does – and it is stirring up quite a lot of controversy in the process. When stars form, they develop an area of rocks and gases around them, and these rocks and gases can eventually start to group together too form planets.

People used to think that planets formed when these rocks randomly collided, creating bodies with bigger and bigger gravitational attraction, which led to a sort of runaway growth. But this would take a very long time to produce a planet. An alternative theory, backed by this latest discovery, is that planets actually form when an area of greater density within the area of rocks orbiting the star starts to contract, a process that could be complete within several thousand years.

OK, the difference between the two methods of planet formation don’t sound huge, but they have massive implications for scientists trying to understand the origins of our Earth. Let’s just hope that the meeting of the British Royal Astronomical Society (where this discovery was announced) won’t turn into a war between feuding scientists.

Radiation may prevent humans ever going to Mars


It’s amazing that the human race is now close to sending a person to another planet for the first time in the history of civilization – NASA hopes to put a man on Mars by 2030, or at least not too long after. But why will it take 20 years? Well, there are loads of problems scientists have to overcome like the psychological impacts of a 2-3 year Wikipedia / NASA trip, the problem of having enough food and water, and finding a fuel that would be powerful enough to power a heavy craft to Mars.

But there’s something perhaps even more important that people often overlook, and it’s something that could affect long-term missions to the Moon too – radiation from the Sun. It’s proving to be a huge stumbling block.

Our Sun constantly bombards our planet – and everywhere else in the Solar System – with a stream of assorted particles, many of which would be harmful to humans if we were exposed to them. In fact, these ‘cosmic rays’, as they’re sometimes also known, were the main thing that prevented life on Earth originating until a billion or so years after its creation. Only when a few resistant bacteria (and lots Wikipedia / NASA of volcanoes) started producing gases to produce an atmosphere could more advanced life develop.

Any mission to space obviously involves going outside our atmosphere, which means leaving the shield that protects us from solar radiation. Even with complex spacesuits, modern astronauts frequently see white flashes of light as solar particles interact with their eyes.

But if astronauts can cope with solar radiation now (for example on Shuttle missions and at the ISS), why wouldn’t they be able to cope on a Moon base or on Mars?

The problem is that unlike on the Shuttle or ISS, astronauts walking around on the Moon or Mars would have only their spacesuits to protect them. On a Moon base the astronauts would be exposed to radiation for days until they finished building the base, Wikipedia / NASA and on Mars the astronauts would want to spend several weeks exploring to make the 2-3 year journey worthwhile. All that radiation would build up, and could trigger things like cancer and tumors.

What’s the solution? It’s basically just a matter of trying to research better and better lightweight protection that can be used for spacesuits – but that could take many years yet. Let’s just hope it doesn’t take too long.

Check out my last post to find out what happens when solar radiation collides with our atmosphere: aurora. There’s a cool image of aurora from space.

Astronauts snap photo of aurora from space

Unfortunately I’m not lucky enough to have seen the spectacular light display visible every winter  – the aurora. At least not yet. But astronauts onboard the Space Shuttle Endeavour got to see the aurora from a very different perspective before they touched down – they saw the mysterious green light show from above.

So what is the weird green light in auroras? Basically, our Sun constantly bombards our planet with a multitude of particles (the solar wind), some of which interact with Wikipedia our atmosphere, causing gases in the atmosphere to glow. It happens mainly toward the poles in winter because these are the places where the solar wind impacts our planet most.

Green coloring comes from ionized oxygen – there is also a small amount of red/purple/blue from nitrogen.

Post a comment if you’ve had any aurora experiences!

Planet Earth plunges into darkness for an hour


Whoa! What happened to Sydney in the photo above? Was there a major power outage or something?

Fortunately no – although what actually happened was something even more important than a power outage. At 8PM local time on March 29, Sydney was one of the first cities to participate in ‘Earth Hour’, in which households, towns and even major cities around the world turned off their lights for an hour to try to help save our planet. And as you can see from the photos, the effect was quite impressive.

NASA Earth Hour started last year as a Sydney-only event, but this year it’s spread to the whole world thanks to WWF funding. By the time you read this, chances are that it will be past 8PM in the U.S., where buildings from the CNN Center in Atlanta to the Golden Gate Bridge in San Francisco will be thrown into darkness.

It’s all very well doing publicity stunts like Earth Hour, but do they really make a difference? Skeptics would say they’re just a gimmick – people are more bothered about the excitement of a candlelit dinner than about the real message of Earth Hour.

NASA But I really do think it will make people think. In some cities office workers were forced to turn their lights off on Friday evening so that they didn’t have to go in again on Saturday – maybe next week they’ll remember to do it again. And of course any publicity about saving the environment is always a good thing.

Oh yeah, and there’s one other huge advantage of having lights out for an hour – as you can see from the Sydney photo, the normally orange, light-polluted sky turned black during Earth Hour, making it one of the only times Sydney residents can ever see the stars above their heads.

Let’s just hope that Earth Hour can become an annual tradition all around the world. Put March 29 in your 2009 diary!

Shuttle Endeavour touches down safely in darkness

 NASA / National Geographic

It blasted off in darkness two weeks ago and has now touched down again at Cape Canaveral in the middle of the night. But Space Shuttle Endeavour’s mission was certainly nothing to be dark and depressed about – it successfully installed a huge robotic arm form Canada to the ISS, as well as delivering the first part of the huge Japanese space lab Kibo. (Click here for more on what Endeavour has been doing these past two weeks)

The great news is that we only have another couple of months or so until the next Shuttle launch – Discovery is scheduled to launch in late May. Its fuel tank was taken to the Kennedy Space Center Wednesday.

Is it really worth all these missions to build the ISS? The ISS is now 70% complete, and it certainly is not useless. Loads of important scientific research is being carried out as you’re reading this, and it has also been a vital exercise in seeing whether different countries can collaborate to create something so technologically advanced.

Here’s the video of the touchdown: