NASA’s twins that could save our world

Wikipedia Imagine a billion tonnes of scorching hot gas and radiation being hurled toward you – it’s not the sort of thing you come across every day.

This is actually something our Sun does on a regular basis, although fortunately for us our atmosphere stops anything too dangerous getting in and hurting us.

But satellites, as well as any astronauts in space, feel the full force of a Coronal Mass Ejection (CME) – as these massive bursts from the Sun are known – and they can be really dangerous.

That’s why NASA decided to launch the Stereo mission, two twin satellites that give us unprecedented views of CME’s – something that would be vital if a CME was ever to come toward us. (Click here for two interesting videos from Stereo)

And it’s not just about damage prevention – we’re learning loads about the Sun too like new footage from Stereo showing just how powerful solar bursts can be as they rip the tail off a comet. The Stereo probes are telling us loads of things we didn’t know about our parent star.

BBC NewsSo why are there two probes in Stereo – wouldn’t just one have been cheaper? The whole point of Stereo is to give us a 3D view of the Sun – just like having two eyes a small distance apart helps our brains give depth to our vision, the two Stereo probes can give us a three-dimensional view of our Sun because one follows a path slightly in front of Earth’s orbit, and its twin trails on behind.

What would happen if one of these CME’s flew straight into our planet? Something not many people realize is that the effects on our lives could actually be huge. For a start many satellites would be knocked out, meaning no television, GPS, weather forecasting and more for a few days. And then there’s cell phones, the internet, and anything else that needs satellites to work.

Wikipedia The good news is that thanks to Stereo, we will be given a few hours’ warning if a CME is heading toward our planet, giving operators vital time to shut down any satellites in the path of the Solar blast, as well as making sure any astronauts are safely inside radiation-proof areas.

The wonderful Stereo probes are yet another example of why scientific research isn’t just about proving some professor’s theory or doing some irrelevant calculations – it really could save our lives. Of course, until the day when a CME is headed our way, it’s always fascinating  to discover more about our amazing Universe.

Interested? Read about how radiation could prevent humans from ever going to Mars.


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.

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!

Total Lunar Eclipse this week – watch the Moon turn blood red

The lunar eclipse of March 3, 2007 | Image: WikipediaA lunar eclipse may not match the magic of an eclipse of the Sun, but it is still one beautiful sight.  First of all the circle of the Earth gradually covers up more and more of the Moon, like the Earth does to the Sun in a solar eclipse, then if the conditions are good, the Moon develops a beautiful blood-red hue.

The good news is that it will be possible to see this spectacle in Europe and the U.S. this week, on Wednesday February 20. The total eclipse will be visible from 10:01 to 10:51pm ET (add 5 hours for GMT), with a partial eclipse visible for a couple of hours before and after. (Click here for an excellent guide from Sky & Telescope)

So what exactly is a lunar eclipse, and what’s with the red coloration? Basically, it’s when the Sun, Moon and Earth align in a certain way so that the Earth is directly in the middle of the Moon and Sun. This means that the Earth blocks all the light going from the Sun to the Moon, so the Moon appears dark.

Or at least nearly dark. Some rays of sunlight pass through Earth’s atmosphere and hit the surface of the Moon. These rays are turned red in color, because the light has passed through so much atmosphere – it’s basically the same reason why sunsets are red. This is what gives the Moon that eerie red color only seen during eclipses.

How common are lunar eclipses? There are actually several every year (click here for details of future eclipses until 2100), though a total eclipse usually only happens once every few years. In fact, the next total eclipse won’t occur until 2010, so you’d better make the most of this one!

This graphic from National Geographic (below) sums up nicely everything you want to know about lunar eclipses.