Hubble

[zigzag]

I believe (since it was about 40 years ago) that in my astronomy course, the theory that in black holes gravity was so strong nothing could escape them, and that it may be possible everything gets sucked through the black hole into another universe.

 

I'd like to have someone explain string theory to me so that I can understand it.

[surfpup]

I'd like to have someone explain string theory to me so that I can understand it.

 

[rocketman]

Well there are a number of possibilities of the universe, but the most believed are that it's one of three: 1) open, 2) closed or 3) flat. The Wilkinson Microwave Anisotropy Probe (I worked on this satellite) suggests that we may have a flat universe, which is an interesting result.

 

I'll let you look up what each of these mean. But I can explain a closed one very simply. Suppose that you start at the equator and walk a straight line. You'd eventually end up in the same spot. The same thing happens in a closed universe. Stated another way. If you had a powerful enough telescope then you would see the back of you head in a closed universe!

[quapman]

Dude,, how, and in what capacity did you work on it?

That's pretty cool.

[badbluesplayer]

Astrophysics is where smart people go to become useless.

[Cougar]

Since the universe goes on forever, has always existed and will always exist, there's no way we are alone.

This isn't your gampa's universe. There is lots we don't know about it, but we do know a few things. Several independent observations indicate that the universe we inhabit began from a very hot, very dense state 13.73 billion years ago (plus or minus about 1%). As Sagan said:

 

"Ten or twenty billion years ago, something happened -- the Big Bang, the event that began our universe. Why it happened is the greatest mystery we know. That it happened is reasonably clear."

[badbluesplayer]

Me and Mittens did an experiment and we figured out that the universe is shaped like a bowline on bite.

 

But only if you ignore everything else you know.

[daveinspain]

So what was before the big bang? Before there was something there had to be nothing so if nothing was there why did something happen?

[gdecantoo]

So what was before the big bang? Before there was something there had to be nothing so if nothing was there why did something happen?

CERN

[zigzag]

Apparently, the universe is still expanding from the big bang. At some point, that expansion will cease and the universe will begin to contract (does time reverse itself?). Like stars, the universe will contract into itself until it becomes an ultra high density entity that will build energy to the point where another big bang will take place, and the expansion of the universe and the formation of galaxies, stars, and planets will resume anew.

[quapman]

Astrophysics is where smart people go to become useless.

 

 

Literally lol'd at that one.

 

Glad I wasn't having a drink when I read that cuz that woulda been a nose spray for sure.

[Tman5293]

So what was before the big bang? Before there was something there had to be nothing so if nothing was there why did something happen?

 

I honestly cannot answer this. No one can. We have no idea what was there before the big bang. Astrophysicists will say with confidence that we know basically everything that happened immediately following the big bang. We can trace the expansion of the universe back to milliseconds after the bang occurred but we still have absolutely no idea what happened before the explosion.

 

Apparently, the universe is still expanding from the big bang. At some point, that expansion will cease and the universe will begin to contract (does time reverse itself?). Like stars, the universe will contract into itself until it becomes an ultra high density entity that will build energy to the point where another big bang will take place, and the expansion of the universe and the formation of galaxies, stars, and planets will resume anew.

 

What you are referring to is the big crunch theory. However, we have reason to believe that this will not happen. The universe should continue to expand for billions of years. Maybe even over a trillion years. By the time the expansion stops Every point of mass in the universe will be so far away from all the other points of mass that they wont have any gravitational effect on each other.

[Cougar]

I honestly cannot answer this. No one can. We have no idea what was there before the big bang. Astrophysicists will say with confidence that we know basically everything that happened immediately following the big bang. We can trace the expansion of the universe back to milliseconds after the bang occurred but we still have absolutely no idea what happened before the explosion.

 

What you are referring to is the big crunch theory. However, we have reason to believe that this will not happen. The universe should continue to expand for billions of years. Maybe even over a trillion years. By the time the expansion stops Every point of mass in the universe will be so far away from all the other points of mass that they wont have any gravitational effect on each other.

 

I've self-studied this stuff for years and years, read over 150 books on the subject. These are good answers, Tman.

[badbluesplayer]

Once you get a PhD people think you're smart about everything. That's why Neil Nicevoice there can yammer about the origins of life and everybody takes him as some sort of expert.

 

He could talk about how to breastfeed and everybody would be taking notes.

 

[badbluesplayer]

The best way to deal with astrophysics is to learn newtonian mechanics and relativity and that stuff when you're a freshman so you can go on to bigger and better things, like engineering, before you get to junior year.

 

That way you don't end up teaching physics on some bulletin board somewhere.

 

[zigzag]

So, education without application is useless, eh?

[Pin]

The probability that we are alone at any given time (relative to earth time) would seem extraordinarily low given the age and size / extent of the universe. However, it is another question entirely whether the concept of other intelligent beings has any real meaning other than the speculative.

 

The Fermi question is the key: where are they? Once you seriously consider aspects of immense size and age that question becomes dominant. If intelligent life arises frequently within this immense space then we SHOULD haver come across it by now IF it has any capacity to sustain and develop into a star spanning civilisation. And yet we do not see this. We have never seen it (pace Eric von Daniken and friends).

 

It seems far more likely to me that, yes, other intelligent civilisations do develop but that as philosopher John Leslie pointed out in his excellent book The End of the World what might (and probably will) befall us will also befall them and does befall them. So, in other words, they never get to be the star spanners of Sci-Fi. It is just in the nature of dynamic, bio-diversity eco-spheres that too many high risks co-exist coupled with self-destructive tendencies of the species itself.

 

But you would think one or two or more would "make it through". But the Fermi question remains: where are they?

[zigzag]

Methane gas exists in the atmosphere of many planets and moons.

 

Methane Life

 

Alternative biochemistries.

 

Alternative Lifeforms

[Tman5293]

Once you get a PhD people think you're smart about everything. That's why Neil Nicevoice there can yammer about the origins of life and everybody takes him as some sort of expert.

 

He could talk about how to breastfeed and everybody would be taking notes.

 

 

 

The best way to deal with astrophysics is to learn newtonian mechanics and relativity and that stuff when you're a freshman so you can go on to bigger and better things, like engineering, before you get to junior year.

 

That way you don't end up teaching physics on some bulletin board somewhere.

 

 

You're really upset about this aren't you? Though I'm not sure why. I considered majoring in engineering, specifically computer engineering, but I have a greater passion for space and science than I do for computers. While I enjoy working on computers and building them, I would rather spend my life studying astrophysics. Besides, there are plenty of job opportunities out there for someone with a degree in physics. You make it sound like a worthless degree.

[surfpup]

He could talk about how to breastfeed and everybody would be taking notes.

 

Yet when I do this people think it's creepy!

[Rocky4]

You're really upset about this aren't you? Though I'm not sure why. I considered majoring in engineering, specifically computer engineering, but I have a greater passion for space and science than I do for computers. While I enjoy working on computers and building them, I would rather spend my life studying astrophysics. Besides, there are plenty of job opportunities out there for someone with a degree in physics. You make it sound like a worthless degree.

 

40% of graduates wind up with a job that utilizes their degree. I've heard many stories of people who lie (dumb down) their college degree on resumes to get menial jobs.

[Tman5293]

40% of graduates wind up with a job that utilizes their degree. I've heard many stories of people who lie (dumb down) their college degree on resumes to get menial jobs.

 

The other 60% chose degrees in fields that have a low demand for new workers. If they would have majored in a field that is in high demand then their chances of getting a job would have been significantly higher. Right now the fields with the highest demand for new workers are science, math, engineering, and computer sciences. Some of those fields are in such high demand that employers are struggling to find people to fill their open positions.

[Rocky4]

The other 60% chose degrees in fields that have a low demand for new workers. If they would have majored in a field that is in high demand then their chances of getting a job would have been significantly higher. Right now the fields with the highest demand for new workers are science, math, engineering, and computer sciences. Some of those fields are in such high demand that employers are struggling to find people to fill their open positions.

 

looks good on paper.......

[rocketman]

I got all my degrees in engineering but my postdoctoral advisor was a theoretical physics major turned engineer. He taught me a lot about physics (my first suggested book to read was one of Eddington's book). Many of the best engineers out there are physics majors. In fact, the most referenced book by NASA control engineers is called Spacecraft Attitude Determination and Control, which was edited by James Wertz (I know him very well) who also is a physicist. Most of the book is written by physicists turned engineers.

 

I love having physics majors in my courses. They honestly blow away the engineering students. I'm currently reading Schiff's famous book on Quantum Mechanics (some light reading for geeks!). A lot of the theory is very related to stuff that I do in my own research. I think it's cool that both fields are very closely related.

 

BTW, last fall we saw a 45% increase in declared engineering majors. This is a trend at universities all over the nation. What does that say?

[zigzag]

BTW, last fall we saw a 45% increase in declared engineering majors. This is a trend at universities all over the nation. What does that say?

 

Hopefully it means that qualified students are majoring in engineering instead of business and law to satisfy a job market need for well paid engineers.