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July 3, 2008 6:13 AM   Subscribe

What are some topics in astronomy or cosmology that you find fascinating and mind blowing?

I recently took an introductory cosmology course at the university I attend, and have taken a couple astronomy courses before that. I've also been reading up on the topics a little, and I find everything fascinating.

Previously, I asked the hive mind about what math topics they thought were really cool. That thread brought about many very interesting answers. So now, with the upcoming 'switching on' of the Large Hadron Collider there must be lots of MeFites out there who find this as interesting as I do!

What blows your mind about astronomy or cosmology?
posted by tomcochrane to Science & Nature (17 answers total) 7 users marked this as a favorite
What blows my mind (and the mind of just about everyone involved in astronomy and cosmology, it seems) is the recent discovery that, contrary to the intuitive idea that gravity should be slowing the expansion of the universe, the expansion is actually accelerating. This suggests the presence of an as-yet undiscovered "dark energy", and has enormous implications for our understanding of the nature of gravity, matter, relativity, and the origin (and ultimate demise) of the universe.

I've got it all figured out, but I'm not telling.
posted by dinger at 6:28 AM on July 3, 2008 [1 favorite]

Dark energy; the questions about non-baryonic dark matter (which implies the existence of an as-yet undiscovered particle that forces an extension of the Standard Model); the beginning of our ability to narrow inflationary theory through observations of the CMB; the fact that there's a confluence of evidence coming from the smallest scale (high energy and particle physics) and the largest scale (cosmology and astronomy) that are painting a very strange picture of the universe... these are what I find exciting.

My second book, Alpha & Omega, goes into these ideas (and what the LHC can tell us).

(Incidentally, my first book, Zero, was mentioned in the earlier thread about cool mathematics.)
posted by cgs06 at 6:49 AM on July 3, 2008 [2 favorites]

That the Pioneer Spacecraft appears to be slowing down and no one exactly knows why.

I've got it all figured out, but I'm not telling.
posted by three blind mice at 6:51 AM on July 3, 2008 [2 favorites]

Forget acceleration or deceleration of expansion - the simple fact that space itself is getting bigger is pretty damn freaky.
posted by Tomorrowful at 7:15 AM on July 3, 2008

Dark matter.
posted by at 7:33 AM on July 3, 2008

I'm fascinated by extrasolar planets. Intuitively, I always expected we would find evidence of planets orbiting other stars, but when exoplanets were first discovered, my mind was blown.

I'm also fascinated by Gamma-ray Bursts, because of their sheer magnitude. The only explosion larger than a GRB is the Big Bang.

I find both topics mind-blowing because the discovery of GRBs (late 60s, classified until 1973) and exoplanets (1992) are both very recent. I couldn't read about either in the C.B. Colby books in my grade school library.
posted by Fat Guy at 7:40 AM on July 3, 2008

My mind is still blown just by the basic mechanics of special relativity--time dilation, the twin paradox and all that.
posted by LionIndex at 7:50 AM on July 3, 2008

Here's a more pedestrian idea than dark matter:

All the gold on earth was created in a supernova explosion. The were not created in the sun or anywhere else in the solar system.

So all the gold you see around you was formed countless billions of year ago and countless light years away during the catastrophic violent deaths of massive stars. It drifted, accreted, and arrived on our humble planet. All we've done is reshape it. But it is still exactly the same gold as it was the day is was born in that faraway star.

This is also true of every element heavier than iron (See explosive nucleosynthesis).
posted by Pastabagel at 8:06 AM on July 3, 2008

I'm still trying to figure out what space and time are expanding into. Pre-Big Bang, there was no space and no time. What does this say about the environment into which they are expanding? Clearly it is able to contain space and time.

But why? What is it?
posted by Guy_Inamonkeysuit at 8:16 AM on July 3, 2008 [3 favorites]

The implication (dervived from string theory, the relative weakness of gravity compared to other forces, the anthropomorphic principle and some aspects of quantum physics) of a multiverse: that our universe is simply one of untold billions of other universes, like a tiny bubble in a sea of space-time foam. That new universes are "born" all the time, at every brush of one brane against another.
posted by Bora Horza Gobuchul at 10:03 AM on July 3, 2008

Honestly it's that most astronomy involves phenomenon not observable by the naked eye. I can understand looking through a telescope and *seeing* something, but analyzing data from a radiotelescope or inferring the presence of a star based on arcane phenomenon is pretty amazing to me.
posted by electroboy at 10:09 AM on July 3, 2008

A while back I stumbled across a paper describing how circularly polarized light in certain parts of the universe could lead to an increase of molecules of a certain chirality--the sort of homochiral molecules required by life-as-we-know-it. I love the idea that light from distant stars, polarized by vast clouds of interstellar dust, could influence interstellar molecules that formed the origins of life on Earth. The vastnesses of astronomy linked to the microscopic realms of molecular biology. Here's an abstract on the subject.
posted by fermion at 10:24 AM on July 3, 2008 [1 favorite]

1.The sheer scale of it all, both in space (distances) and in time (age). It's unfathomable. There are at least one hundred billion galaxies in the visible Universe. And in our galaxy alone (the Milky Way) there are about 300 billion solar systems.

2.Stack those numbers up and it's seeming pretty damn likely that there's other intelligent life out there. (Yes, I know there's a healthy debate about this, and that I'm oversimplifying. But still.)

3.Black holes. A three-dimensional hole? That's relatively insane. But that it's so "deep" (i.e. gravitationally potent) that light falls in? *boggle*

4.As others have mentioned already, the mystery of the Universe's accelerating expansion.
posted by Robson at 10:42 AM on July 3, 2008

I did a first year astronomy course a few years ago, and the thing that struck me was the existence of pulsars, or neutron stars. Planets that are 30km across yet weigh more than the sun. More than the sun! I think the example was that a teaspoon on material from a pulsar would weigh as much as the earth.

That's just insane.

(It's been a while, I could just be imagining those numbers)
posted by twirlypen at 4:18 PM on July 3, 2008

That the Pioneer Spacecraft appears to be slowing down and no one exactly knows why.

Slowing down and off-course, right?
posted by ifthe21stcentury at 3:42 AM on July 4, 2008

"Alpha & Omega" is one of the best books in the genre I've ever read. For whatever reason, it kept me interested cover-to-cover.
posted by Goofyy at 6:09 AM on July 4, 2008 first book, Zero...

Wow, I really liked that book; I had no idea it was by one of MeFi's own! I will definitely be looking up your next one.

But to actually answer the question, the Hubble Deep Field blows my mind.
posted by TedW at 3:59 PM on July 4, 2008

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