Intro to Astrophysics

November 17, 2014 9:11 AM

I'm looking for resources that will give a layperson like me an interesting introduction into astrophysics, specifically how distant celestial bodies interact over vast periods of time.

There have been some amazing things in the news lately about space. I find myself absorbed with the increasing pace of discovery of asteroids. The fact that the ESA just landed a robot on a comet completely blows my mind. And then there's Hubble's ridiculous deep-field composite photo of a tiny piece of the universe.

There is no way I could begin to comprehend the complexities of astrophysics (heck, I still have trouble wrapping my head around moon phases), but I'm really interested in how celestial bodies interact over great distances and vast time periods. For example, I recently learned how Jupiter's gravitational field "shepherds" thousands of asteroids out of Earth's orbit. This is amazing!

But I'm talking even bigger. For example, does the Andromeda Galaxy have any pull (gravitational or otherwise) on Earth over billions of years?

posted by joebakes to Science & Nature (8 answers total)

The Andromeda galaxy is actually going to collide with the Milky Way in about 4 billion years, and the two galaxies will eventually merge. This is unlikely to affect the Earth directly (other than probably looking cool).

If you're interested in the "astronomical events that could kill you" sub-genre of astronomy, I recommend Phil Plait's book Death from the Skies.
posted by Anne Neville at 9:27 AM on November 17, 2014

In case you have (or have access to) Netflix, I want to mention a series of lectures by Neil deGrasse Tyson under the title "The Inexplicable Universe." Not sure it approaches the topic from the angle you're looking for, but worth a look.
posted by Flexagon at 11:01 AM on November 17, 2014

Astrophysics can be a really math heavy subject or it can be fun. [Ok, kidding, kind of] Cosmos - both series, might be something worth a look.

I love the subject both because and despite that it pisses me off.

Here, have some quantum tunneling.

I sent up the physicsmatt symbol.
posted by vapidave at 11:33 AM on November 17, 2014

You could check out some astronomy and astrophysics classes on iTunes U or similar. I can't speak to any specific courses other than the one I actually took (which is Professor Filippenko's Intro to General Astronomy, and is still available via podcast here and which I very much enjoyed), but a podcast/webcast of a college class might be a good way to get a good grounding in the subject, especially given that the podcast classes tend to be the intro/survey courses.

For example, here's an Intro to Astrophysics course, complete with youtube videos of slides from the lectures. I happen to be linking to Berkeley's online courses just because I'm familiar with them and where to find them, but most of the other big universities have podcasts/webcasts available too. If you're really dedicated, you could probably dig up the syllabi and textbooks too.
posted by yasaman at 12:47 PM on November 17, 2014

You might be interested in the astrophysics simulator game Universe Sandbox. I got it on sale on Steam for like $3. It includes a pre-made simulation of 2 galaxies merging. You can also play around with smaller scale stuff like solar systems and see how changing the mass, velocity, distance etc. affects the way the stars and planets interact.
posted by Librarypt at 1:13 PM on November 17, 2014 [1 favorite]

Did you know that we know of 1516 confirmed planets outside our solar system, and have another 3359 planet candidates to work through? Try out the link to the Exoplanet db and play with some of the example plots to get a feel for one of the fastest-growing areas of astronomy today.

If you just want to learn more about the general set of astrophysics topics, the first 5 matches in this search for iTunes University Astrophysics all look good to me - Charles Bailyn, Yale, Oxford, Chicago...
posted by RedOrGreen at 9:04 PM on November 17, 2014

I should probably have tried to answer this question at home where I could look at the pop-sci books on my shelf, as apposed to at work, where all I have is the science-sci books. Misner, Thorne, and Wheeler is certainly a complete discussion of gravity, but I sort of doubt it is what you are looking for. I always recommend Sean Carroll's books for top-notch science writing, but he's more cosmology and less astrophysics. I haven't read it yet, but Prof. Katherine Freese has a new book out on dark matter. She's a big name in the field, and the reviews seem good.

For random fun science facts and commentary, I would maybe suggest following some of the scientists involved in astrophysics on twitter. We all tend to get very excited around major discoveries, conferences, airings of Cosmos, what have you, and drop various 140-character pearls of astro-wisdom. In addition to people you almost certainly have heard of (your Neil dGTs, your Bobaks Fedowskis, and your Phil Plaits), I might recommend some people you may not have heard of but probably should: @AstroKatie (Katie Mack), @planetDr (Sarah Horst), and @shaka_lulu (Lucianne Walkowicz) and I'm sure I'm forgetting many others, but you'll figure it out. In default mode, science twitter tends to be low-level sarcastic complaints about grant writing and lab mishaps, but when something interesting is happening, it can turn into an actually useful way to get information.

Alternatively, if you find something fun and relevant, make a good FPP out of it. Who knows what people might contribute to the discussion?
posted by physicsmatt at 6:48 AM on November 18, 2014

I don't follow the popular science book or social media scene very closely, but others have covered that well. However your most direct question has a remarkably simple answer. Yes, the Andromeda galaxy does indeed exert a force on the earth. It does so for the same reason that Jupiter shepherds asteroids (and why gaps in Saturn's rings are controlled by the so called shepherd moons): quite simply, gravity is a long range force that cannot be shielded. Unlike the electric force (technically the electromagnetic force), which has both positive and negative charge, gravity has only one charge, which we call mass. Thus, unlike the electromagnetic force, which can be canceled out by equal amounts of positive and negative charge, gravity always attracts.

This is one of the greatest and deepest ideas in astrophysics: on the largest scales, gravity shapes everything while electromagnetic fields carry the information to us in the form of light. As a concrete example, we have made a ludicrous amount of progress in understanding the large scale structure of the universe by assuming that it contains solely dark matter interacting by gravity only. Then we paint galaxies that emit light on the clumps of dark matter that form, and look and behold, the statistics of these fake galaxies match the observed distribution of galaxies in the real universe. There is a tremendous amount of work that goes into such statements of course, but that basic idea is the outcome. Gravity is a very simple idea with astounding consequences. Also, everything you mentioned requires only Newtonian gravity of the sort taught in high school. (The math on the other hand is a bit above the high school level, though.)
posted by q9f9A at 5:09 AM on November 19, 2014