Billion dollar telescope snaps galactic head-on The first images are in from the immense ALMA radio-telescope array, under construction at 16,500 feet in the Chilean desert, and they reveal a galactic collision of near-unimaginable violence and equally mind-boggling beauty. The images show the collision of paired galaxies, NGC 4038/4039, which combine in what's become known …
It might look messy from here, but stars are normally so far apart that the chances of there being individual stellar collisions is exceedingly small. The merging of galaxies per se would present no real threat to life. It's your run-of-the mill local supernovae and gamma ray bursts that you've got to worry about: if you're too close to one of those babies, you're going to get frazzled by a shell of radiation as little as ten light seconds thick but enormously more energetic than a typical solar output.
The chances are somewhat better of planetary systems being catastrophically disrupted by gravity interaction due to the various near (in galactic terms) misses though. Let's hope there's no-on at home on any of the planets that get ejected into space, into the nearest star or sent to smack into each other.
And if there are people involved in this celestial nonsense, let's hope they actually got on with building spaceships and space stations and so on rather than just making TV shows and computer games about them.
Remember: "There's nothing cool about CGI if you are about to be squished to atoms by your own moon".
The Andromeda galaxy is so close (couple of million light years) that the local gravitational attraction rate overcomes the expansion rate of the universe. There is something called the Local Group which are all gravitationally bound. I cba to look up how big it is but from memory its several tens of millions of light years across I think.
We ARE moving away from the earth, just at our scale and point in time the universal expansion is so small as to be unmeasurable.
But if the Big Rip theory holds true (and I hope it does, because the idea of the entire universe tearing itself apart before our very eyes is one that holds a lot of appeal for me) this expansion WILL become noticeable at our scale about 50-80 billion years from now.
The Big Rip theory states that as universal expansion accelerates the Hubble radius (the distance from an observer at which the universal expansion rate reaches the speed of light) must become smaller over time.
Eventually, other galaxies will be moving away from us (technically) faster than light and will therefore no longer exist in our frame of reference - or we in theirs. In the last few years, even other stars will be moving away too fast for us to observe, then the other planets and the sun, and finally, in the last few seconds, the moon.
At the very final moment of life, your feet would be accelerating away from your head faster than light, and each of us will be in our own private universe for a fraction of a second, before the atoms, subatomic particles and even the quarks and strings that compose them are also ripped apart by the accelerating expansion.
I'd love to live to see that happen!
I have a friend who didn't like the fact that his wedding photos had a clear blue sky, so he photoshopped in clouds. It is pretty easy if you have clear sky.
Having said that though, the Atacama desert does get clouds. As a rule of thumb it has overcast mornings and cloudless afternoons. In fact there is some research out there that tries to measure the effect of the clouds compared to the cloudless afternoons - eg: http://www.agu.org/pubs/crossref/pip/2011JD015905.shtml
My suspicion is that these clouds are real.
You obviously have never been to Australia then. Here in Adelaide, it can be sunny and clear on the plains while it's pissing with rain in the hills just 5 kilometres away - much less 10 miles (16 km). In fact, it's not unusual to see "rain walls" here - as in, it's pissing down at my house but my neighbour's house is bone dry.
I'm not saying the same conditions prevail at the Atacama but here at least, 10 miles is more than enough distance to be experiencing completely different weather!
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