Saturday, 16 April 2016

Latest news from interstellar space

So, it turns out there's a huge galaxy sitting right next to ours. Well, huge in terms of dwarf galaxies. Crater 2 has an effective half-light radius of 1100 pc, so that makes it at least 7000 light years across. It's the fourth largest satellite of the Milky Way (after the Magellanic Clouds and SagDEG), orbiting at relatively close distance (only 120 kpc), so it's quite astonishing that it's remained undetected until now. It is, however, remarkably dark - one of the dimmest galaxies ever seen. A vast collection of stars just swinging past ours for billions of years and we've only just noticed. It makes you wonder what else is out there; researchers are already planning ways to search for dark galaxies.

There's also the discovery of a new category of exoplanet: superearth-sized bodies which have been stripped of their atmospheres by close proximity to their parent star. If confirmed, these irradiated desert worlds would fill a gap in the variety of exoplanets already known, and give us a look at what might lie in wait for our own Earth in the distant future as the Sun expands.

Then there's the spectacular news that Stephen Hawking is teaming up with a wealthy Russian eccentric to begin research into a new space programme. It's summarised here at the Guardian, but the upshot is that we could be receiving data directly from Alpha Centauri in the next few decades. Hawking proposes that research and technological development could make the proposal, involving a swarm of tiny spacecraft accelerated to extreme velocities by laser beams, could be feasible in ten to fifteen years.

If successful, the starprobes could reach up to a fifth of lightspeed, allowing at least some of them to make the trip to Alpha Centauri in a mere twenty-five years. Once there, they will begin transmitting data back at lightspeed, meaning another four-and-a-half years before we receive updates. Sadly, Hawking will never get to see the fruits of the project, but a future generation of astrophysicists could be studying that data for years. If successful, the project could also revolutionise exploration of our own solar system - searching for the supposed ninth planet, for example. (Personally, I'll believe that one when there's some real evidence.)

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