Large Hardon Collider

[Eliseos]

Top Gear UK did a pretty awesome piece on the lunar buggy, the past one and the new one. James May takes the new one around for a drive and shows what would have been the newest rover.

Torrent links for the episode at http://www.finalgear.com/shows/topgear/16/6/ the clip is near the end of the episode.

[Woozie]

[LiveJournal] So anyways, that "Advanced" Linear Algebra class I was complaining about:

As I said before, it's supposed to be a part II to regular linear algebra, but it has somehow turned into linear algebra I: The Remix

As a result, I stopped going to class. It was too boring for me to take. Last Wednesday we had our midterm. I come to class 10 minutes late and the professor tells me "I didn't get a chance to tell you because you didn't come to class...I started giving the tests out at 8 so everyone has an extra hour" (it was 9 when I came in). So I missed an hour of the test. Since he was giving us 2 hours for the test, I figured it was probably a really long test.

He hands me the exam and there's only four questions. And I don't mean four questions as in "1 part a b c d e, 2 part a b c d e, etc", I mean there's really only four things to be answered. I finished the exam in 10 minutes and was the first to walk out despite everyone else having an hour head start.

Friday was a snow day, so Monday was the first day of class after the exam. I didn't go. I decided to come today because I figured homework was probably assigned on Monday and I needed to figure out what it was. When I get in class, I notice everyone sitting down taking an exam. The professor explained that the exam scores were so incredibly low that he's making everyone retake the exam. He said I could retake it too, but he would highly recommend not doing so.

He handed me my exam. I got a 100%

How the heck did everyone else fail this exam? They got an hour head start, came to class every day, and got a couple of review sessions. On top of that, this class has yet to cover anything that wasn't already covered in Linear Algebra (despite us being in the middle of the semester). This is ridiculous.

[/LiveJournal]

Edit: Oh, and I was right, he did assign homework on Monday. It's on eigenvalues. And I don't mean some advanced stuff using eigenvalues, I mean the basic eigenvalue problems you all solved in regular Linear Algebra. In other words, even after the midterm, we're still not covering anything new or advanced.

Edit 2: Here, I'll contribute something to this thread to make up for LiveJournaling it up

Two Planets Found Sharing One Orbit

[spoiler]Buried in the flood of data from the Kepler telescope is a planetary system unlike any seen before. Two of its apparent planets share the same orbit around their star. If the discovery is confirmed, it would bolster a theory that Earth once shared its orbit with a Mars-sized body that later crashed into it, resulting in the moon's formation.

The two planets are part of a four-planet system dubbed KOI-730. They circle their sun-like parent star every 9.8 days at exactly th

[Woozie]

Sorry my post got cut off and now these computers are being stupid again and not allowing me to edit my post or post a reply that finishes the previous post. So anyways

http://www.newscientist.com/article/...one-orbit.html

Someone can post the full texts if they want. My connection isn't allowing me, for some reason.

[Eliseos]

You should just become an engineer Woozie, we don't repeat material like that.

And:

Buried in the flood of data from the Kepler telescope is a planetary system unlike any seen before. Two of its apparent planets share the same orbit around their star. If the discovery is confirmed, it would bolster a theory that Earth once shared its orbit with a Mars-sized body that later crashed into it, resulting in the moon's formation.


The two planets are part of a four-planet system dubbed KOI-730. They circle their sun-like parent star every 9.8 days at exactly the same orbital distance, one permanently about 60 degrees ahead of the other. In the night sky of one planet, the other world must appear as a constant, blazing light, never fading or brightening.


Gravitational "sweet spots" make this possible. When one body (such as a planet) orbits a much more massive body (a star), there are two Lagrange points along the planet's orbit where a third body can orbit stably. These lie 60 degrees ahead of and 60 degrees behind the smaller object. For example, groups of asteroids called Trojans lie at these points along Jupiter's orbit.


In theory, matter in a disc of material around a newborn star could coalesce into so-called "co-orbiting" planets, but no one had spotted evidence of this before. "Systems like this are not common, as this is the only one we have seen," says Jack Lissauer of NASA's Ames Research Center in Mountain View, California. Lissauer and colleagues describe the KOI-730 system in a paper submitted to the Astrophysical Journal (arxiv.org/abs/1102.0543).


Richard Gott and Edward Belbruno at Princeton University say we may even have evidence of the phenomenon in our own cosmic backyard. The moon is thought to have formed about 50 million years after the birth of the solar system, from the debris of a collision between a Mars-sized body and Earth. Simulations suggest the impactor, dubbed Theia, must have come in at a low speed. According to Gott and Belbruno, this could only have happened if Theia had originated in a leading or trailing Lagrange point along Earth's orbit. The new finds "show the kind of thing we imagined can happen", Gott says.


Will KOI-730's co-orbiting planets collide to form a moon someday? "That would be spectacular," says Gott. That may be so, but simulations by Bob Vanderbei at Princeton suggest the planets will continue to orbit in lockstep with each other for the next 2.22 million years at least.

[Woozie]

Thanks, Eli. For some reason the internet here in the physics department doesn't let me post in this thread much. Every time I tried to finish that post or repost it, I timed out.

And half of this class are engineers, so I think I'd have this problem even more if I became one. Plus I'd have to order myself executed when I finally take over the world.

According to the professor, the engineers are the reason he's teaching this as Linear Algebra I instead of Advanced Linear Algebra. He says they haven't taken regular linear. If that's true they shouldn't be in this class. If that's not true they have no excuse for doing so poorly. I've done Advanced Engineering Math I and II, so I know that linear algebra is covered thoroughly in the engineering undergrad curriculum. These engineers already have a bachelors, so I don't know if they skipped that class or what. No matter what the situation is, something still isn't right.

[Ferion]

By it being Linear Algebra I again, do you mean it's proofed based linear algebra where you actually look into the properties of linear transformations and stuff like that? Or is it a "Here's a matrix, do this to it" linear algebra class? Since it's grad school I really can't imagine it's the latter. Either way having an extra hour for an exam and the whole class failing is pretty crazy.

[Azull]

Is there any word on the age of the star they orbit?

If the data manages to get verified wouldnt this potentally be a bigger boost to advanced life exisiting somewhere then finding reasonable sized planets in the habitable zone of a star? With all the benefits the Earth gained from the moon forming incident it seems like they are generally forgotten when it comes to just trying to find stuff thats the right size/place

[Woozie]

By it being Linear Algebra I again, do you mean it's proofed based linear algebra where you actually look into the properties of linear transformations and stuff like that? Or is it a "Here's a matrix, do this to it" linear algebra class? Since it's grad school I really can't imagine it's the latter. Either way having an extra hour for an exam and the whole class failing is pretty crazy.

It's a little bit of both, but more of the latter. But so was basic linear algebra. This class is no different than regular linear algebra (the professor even uses the same book here that he uses in regular linear. He originally intended to go over the later chapters in the book that would be covered in regular linear algebra, but he changed his mind and started from the beginning, thus making this into regular linear algebra).

[Woozie]

Is there any word on the age of the star they orbit?

If the data manages to get verified wouldnt this potentally be a bigger boost to advanced life exisiting somewhere then finding reasonable sized planets in the habitable zone of a star? With all the benefits the Earth gained from the moon forming incident it seems like they are generally forgotten when it comes to just trying to find stuff thats the right size/place

The reason the benefits of the moon are forgotten when searching for extraterrestrial life is because the moon isn't necessary. If we had no moon, we would still have life, it would just be a whole lot different. Microscopic life may have still formed. The question is whether or not larger, macroscopic life would survive. All of the delicately balanced conditions that allow the Earth to be the way it is only becomes important when you're specifically looking for intelligent life. If all you want is life period (i.e. you don't care about size or intelligence, you're just looking for anything that's alive), then all we think we need is a planet in the right position with the right building blocks.

This is a boost to the credibility of our current model of the moon's formation though. But we're a long way from being able to look for planets with the very specific conditions necessary to create such a perfect system that we have that would make intelligent life (as we know it) likely. What I'm saying is that this probably doesn't make life in general more likely since life in general doesn't require as delicate of a balance of favorable conditions as we have here on Earth. It may make intelligent life more likely though if we make some assumptions about how similar intelligent life and their planets have to be to humans and our planet.

Besides, to have a moon that is so absolutely perfect could be so rare that it's not worth looking for. Maybe that's part of the reason people don't look for it when searching for life. If we want a good chance of finding intelligent life, we had better hope that there are other sets of conditions that could produce it as well.

[Kaylia]

@Woozie
Do you think you could send me a few .pdf that you're using in your linear algebra class (or book reference) if you don't mind?

Linear algebra is probably my biggest weakness at the moment, but I'm not exactly sure where to start on my own. I know a lot from physics class, but everytime I pick a book at the library, it seems far too advanced for my need. I guess I could also go ask a teacher from the mathematics department, but I'm lazy.


@double planet orbits news
If such system is stable, I'm curious to see what caused the Earth to collide with that other object.

[Plow]

As Max pointed out, there's absolutely no way that could happen in our universe. You have to realize that the gravity of a black hole is really no different than that of a star. If the sun was replaced by a black hole with the same mass as the sun, the Earth wouldn't even notice (well...we would notice the lack of heat and light, but gravitationally, the entire solar system would remain unchanged. Earth would still revolve with the same speed like nothing ever happened. The same is true of everything else in our solar system). The geometry of a black hole allows much stronger gravity than you would see from stars if you're very very close to it. But from a distance, there's absolutely no difference.

So, for the same reason you would be surprised if all the matter in the universe was going towards some huge star, it would be surprising if all the matter in the universe was going towards some black hole. In fact, we practically never see any two stars collide, and for that same reason, black holes probably wont do so either since their orbital dynamics are the same.

Gravity decays big time with distance. In fact, distance matters more than mass when it comes to gravity. Because of this (and for other reasons), you will never see our entire galaxy collapse into the supermassive black hole at the center of our galaxy. So all the black holes in our own galaxy will never come together. Then, as Max pointed out, the black holes in different galaxies will never come together because of the expanding universe. If two galaxies are close enough, then they may collide and their super massive black holes may join (in fact, this is going to happen to our own galaxy in a few billion years). But most are galaxies out there so far away that the gravity between them and almost every other galaxy is negligible. In addition, those galaxies are moving away from almost every other galaxy with high speeds because of the expanding universe.

But, theoretically, someone may suggest that there is some universe where this could all happen. The point I'm trying to make is that although most of your ideas cannot work in our universe, there's no reason to rule out them happening in some other universes, so it's still worth considering. Of course, we don't have the tools (yet) to really consider it, but it's one of those things that is really fun to think about and could be something we can actually study in depth in the future.

thanks for this btw, that's like exactly what I was trying to figure out

[Woozie]

I'll send it when I get home from school (about 12 hours from now), Kaylia.

[Ferion]

The Linear Algebra class I'm currently taking is using "Linear Algebra" by Friedberg, Insel, and Spence. It's not too rigorous but definitely above an intro class, depending on what you're looking for Kaylia it might be pretty good. Only problem with it is the authors love to skip steps in examples, which I hate.

[Woozie]

That's the same one we're using. I have the PDF for the second edition (which I'm about to send to Kaylia in a bit) but we're using the fourth edition. He uses this same book for regular linear algebra as well. However, I had a different professor for regular linear algebra, and the book we used was by "Lay" (I think his first name was David). I'll send that too if I can find it. Honestly, I liked Lay's book better, (partially because he makes awesome potato chips).

[Kaylia]

I'll send it when I get home from school (about 12 hours from now), Kaylia.

Thank a lot! Hopefully, it will be around the level I'm looking for.

[Woozie]

Check your PMs, Kaylia.

[Shiroikage]

Any chance you could hit me up with that too?

[Woozie]

Sent. I think David Lay's book is on my old computer (which is broken) and I can't find it online either, so I only sent Friedberg's.

[Woozie]

Completely off topic, but I think Kaylia speaks French. What does this mean?

"chaque pave de notre bonne ville de Paris est rogue"

The online translator thing I used made no sense to me.

[Mizango]

Shiro probably does too, considering that Canadians are considered "lesser French", to a certain degree.