The Cosmos

[Rhaps]

This is a thread for any and all intelligent astrological conversation.
I personally am interested in Gliesa 581, the most earth-like planet we've stumbled upon. Sure it's impossibly far away, but with ion propellant technology we've made I think reaching near lightspeed is possible, therefore easing time expendature.
Note: I'm not sure if ion engines can get going fast enough to reach near lightspeed, all I know is that they keep at constant positive acceleration.

[smurphy]

But one has to take into consideration that life on earth reaching such sophisticated levels was a mere fluke if we are to go by Darwins theory. Though I have no doubt that life reaching the early plantae stages is entirely possible on this Gliesa 581 the chances of reaching it within a lifetime with current technology is null and that techology needed still wont be acquired within a few centuries. If these ion engines are constantly accelerating it might take a few decades to reach lightspeed aka 299 792 458 m / s. Even if the distance were far even for lightspeed it would not be a problem if lightspeed could be attained quickly as time slows down in lightspeed. I predict habitation of such planets by 2700 myself though science has come so far in 100 years so hopefully it might be quicker as regarding earths dwindling resources.

[Rhaps]

Gliesa isn't seen as a study for new life, it's viewed as a new home. Like you said, our resources are dwindling and we need a new home. So, maybe this is the answer to our galactic real estate search

[OnOneRyder]

First off, by the laws of physics which we accept today...you cannot reach lightspeed. I may be slightly off in my wording off this, but for matter to reach the speed of light it would need infinite propulsion as it's mass would become infinite as well. Near lightspeed travel theoretically is possible, however we do not possess the technology to come anywhere near travelling at this speed. There are theories out there that suggest it's possible, we are nowhere near making use of these methods. The problem with using a propellant method like the Ion thrusters is you need to take with you the fuel you'll consume, and once you get into talk about deep space travel the majority of the fuel needed and consumed will be there simply to propel itself.

I don't think we will be venturing to any planets in the hopes of searching for life. In our solar system perhaps, but even if near light speed travel was a reality there's too much of a gamble involved. Our best bet is to make radio contact with another civilization just to proove to the masses that yes, life elsewhere in fact does exist and it's discovery is very important. There's no doubt in my mind this will someday happen, it's just a matter of both of us being lucky.

[Rhaps]

I agree on that too, actually Hitler's Berlin Olympics have already reached some part of the universe, can't remember which.
But, if about 60-70 years radio message sending time is applicable to all messages, we may get some soon.
But who knows

[Heartless Angel]

It's much more likely that we'll end up terraforming Mars or something than moving to a planet outside of out solar system. At least in our lifetime, though even terraforming probably won't be nescessary in that time. As for moving at the speed of light, there's no doubt in my mind that it will someday be possible, but given what we know now, and technology we currently posess, we can't even come close to propelling a vessel that fast.

[Rhaps]

Well that's kinda the kicker
Near lightspeed may be possible, but to travel at lightspeed we need to have zero mass like light rays.

[Heartless Angel]

Ah, but light DOES have mass. Very small mass, but mass nonetheless. The proof is gravity. Gravity is the attraction between masses, and black Holes can suck in light, therefore light must have mass. So it is possible for mass to move at 3x10^8 m/s. Obviously, larger objects with greater mass would move slower, but really, if we could travel at half that speed we'd be fine.

[OnOneRyder]

The difference is light photons cannot be controlled as other matter can, it's always being emitted from an object and cannot be stopped and held in one place. Therefore they can act very much differently than other matter. Edited because I can't type at night. Dyslexic's of the world UNTIE!

[Heartless Angel]

As of yet we can't make other matter act as light photons. Technology also comes further by the day. I'd honestly be amazed if we DIDN'T figure out how to move at near light speed someday.

[smurphy]

Imagine though if the Hadron collider turns out to be successful and makes technology jump forward a few generations which might make lightspeed possible as scientists may learn to manipulate matter. Anything is possible at this point. Definitely what im hoping for as opposed to earth being swallowed by a blackhole generated by the collider.

[Rhaps]

Have they gotten an OK for the Collider? We risked Global Fallout with the first nukes, and they certainly provided no technological ease besides the short term nuclear energy use, so it'd be a travesty to trash a project of that magnitude.

[M16]

Ah, but light DOES have mass. Very small mass, but mass nonetheless. The proof is gravity. Gravity is the attraction between masses, and black Holes can suck in light, therefore light must have mass. So it is possible for mass to move at 3x10^8 m/s. Obviously, larger objects with greater mass would move slower, but really, if we could travel at half that speed we'd be fine.

Photons do not have mass. Black holes do not "suck in" light. A black hole just has an escape velocity higher than the speed of light. Photons are massless.

[OnOneRyder]

What I really wonder about is where would we be if religion hadn't struck down some of the greatest thinkers to have ever existed. We were making so much progress thanks to the library of alexandria, I truely believe we would have been centuries ahead of where we are now. It's astonishing to learn of some of the things discovered so long ago that had been forgotten or declared lies by the church to later be discovered once again to be true. Eratosthenes for one discovered the earths circumfrance to within a 1% accuracy 200 years before christ is said to be born! Literally more than a thousand years after this it was believed the earth was flat. If these great minds had as much power as the church's did we would be a much more advanced species than we are today.

[midgetbob]

I've looked into the technology loss of the dark ages a lot... while this graph is...a bit cheesy, it's what i could find quickly while being tired.

I'll divulge more information when I'm not rewriting every sentence due to the sandman having me in a choke hold.
http://images.sodahead.com/polls/000...oll_xlarge.gif

[Heartless Angel]

Photons do not have mass. Black holes do not "suck in" light. A black hole just has an escape velocity higher than the speed of light. Photons are massless.

Do you know why Black Holes are Black? It is because light does not escape them, meaning they do in fact suck in light. If it is impossible for matter to move at lightspeed, how would we know that the escape velocitiy was greater than the speed of light, unless we'd seen something moving at the speed of light, which means light, fail to escape it?

[Rhaps]

You guys seem to be getting pretty ragey lol let's move to something where not so much rage can occur
The Pillars of Creation!

[TigermusiQ]

You guys seem to be getting pretty ragey lol let's move to something where not so much rage can occur
The Pillars of Creation!

The book? So Terry Goodkind created us?

Seriously though I think the moon is worth having a closer look at, isn't it recently that they discovered water? That would make a base of operations there and with technology involving using Hydrogen fuel cells as a clean and renewable source of energy ideal (and the moon having craters anyway) there could be a lot of developement on it, perhaps?

As for the Hadron collider isn't that either nothing will happen, to a black hole being created underneath Switzerland?

[smurphy]

Werent the Pillars destroyed by a nearby Supernova? Amazing that the people at the Hubble telescope can view these gas clouds which have already been destroyed but due to the lag we wont see them destroyed for another thousand years( considering the 7000 lightyears distance and that they were destroyed nearly 6000 years ago). Anyone else aware of such other interesting celestial bodies? Im quite ignorant in these matters.

[Trodorne]

so why is it not that a gravitational propulsion be created, by creating a miniature black hole where the energy emitted from it can act as energy for a propulsion system?

[OnOneRyder]

Photons do not have mass. Black holes do not "suck in" light. A black hole just has an escape velocity higher than the speed of light. Photons are massless.

how can we explain gravitational lensing if photons are massless then? i'm not debating they are, i am however intrigued on what this means for space. does this fortify einsteins theories of space time, because we know gravity affects time. does gravity over great distances not just attract objects but stretch space and thus light travelling through it? i hope you can make sense of this as it has been rattling around in my mind. i wish my math skills were greater and i could pursue studies in this

[M16]

Do you know why Black Holes are Black? It is because light does not escape them, meaning they do in fact suck in light. If it is impossible for matter to move at lightspeed, how would we know that the escape velocitiy was greater than the speed of light, unless we'd seen something moving at the speed of light, which means light, fail to escape it?

I'm glad you've enlightened me to this. I never would have known otherwise.

Saying that black holes suck in light is an incredibly simplified and elementary way to look at it. Photons, by definition, are massless light particles. By saying that light can not escape a black hole, we are just stating that the escape velocity is higher than the speed of light.

We can calculate the escape velocity of any object (massive or otherwise) by setting the potential energy of said object equal to the kinetic energy a second object would have to have in order to escape the first object's gravitational potential. The only unknown is the velocity of the second object, so we solve for that. It's one of the easiest calculations in physics. We don't have to see something escape in order to calculate the escape velocity of it.

how can we explain gravitational lensing if photons are massless then? i'm not debating they are, i am however intrigued on what this means for space. does this fortify einsteins theories of space time, because we know gravity affects time. does gravity over great distances not just attract objects but stretch space and thus light travelling through it? i hope you can make sense of this as it has been rattling around in my mind. i wish my math skills were greater and i could pursue studies in this

You've actually pretty much nailed that one right on the nose. Something does not have to have mass in order to exist. Gravitational waves, light waves, and sound waves are all massless, yet we see their effects on light, matter, and energy. Light in itself is actually a pretty obscure and complicated topic.

Gravitational lensing does, indeed, bend light. There's no other way around that. And it's precisely because massive objects bend space-time around them. We just had a pretty in-depth assignment on this for my Astro class, but unfortunately I didn't understand the topic completely and had to copy off of my peers .

The math behind this is way too in-depth to be brought into casual conversation. Essentially, just bear in mind that massive objects bend space-time, and light travels in a straight line along this space-time. If the space-time bends, so must the light so that it continues along its straight path.

[OnOneRyder]

I was right?! Screw university, the next big theoretical physicist stands before you ladies and gentlemen. Space-time is the really tricky concept to grasp though. Trying to comprehend the two without having one without the other numb's my brain. Here's another question then. We know when you have two identical clocks of very precise functions one on the ground will read slightly differently than one in an aircraft due to the differences in gravity, which if you look at it fundamentally is a form of time travel. Now, if gravitational forces warp space time by drawing in objects is the actions a space craft does the opposite essentially "pushing" space time or possibly cutting through it thus speeding it up.

[M16]

I was right?! Screw university, the next big theoretical physicist stands before you ladies and gentlemen. Space-time is the really tricky concept to grasp though. Trying to comprehend the two without having one without the other numb's my brain. Here's another question then. We know when you have two identical clocks of very precise functions one on the ground will read slightly differently than one in an aircraft due to the differences in gravity, which if you look at it fundamentally is a form of time travel. Now, if gravitational forces warp space time by drawing in objects is the actions a space craft does the opposite essentially "pushing" space time or possibly cutting through it thus speeding it up.

You're thinking about this the wrong way. You're right in saying that the two clocks move at different speeds. Look up the "Twin Paradox" if my following explanation does not suffice.

On the surface of Earth, we feel a much stronger gravitational pull than we would out in a space shuttle. It is this gravitational pull that is changing the rate at which time passes. This is a bit tricky, so I apologize for this: All observers, regardless of their (inertial) reference frame, observe time to move at the same rate. However, when we look at (moving) clocks which are outside of our own reference frame, and compare them to the (moving) clocks in our own reference frame, that is when we see a discrepancy in the two times.

That being said, the space shuttle is not "pushing" the time along at a different rate. The space shuttle is just traveling through space-time in a much different rate than someone on the surface of earth, and it is this difference in motion which causes the different passages of time. In a deeper gravitational well, motion through space-time is much (in lack of a better term) quicker than that in a more shallow gravitational well.

Again, I'm really terribly sorry if this did not come out clearly enough. That's unfortunately the best I might be able to explain it.

[OnOneRyder]

I see, I'll definitely check that out but your explanation was very good.

I'm trying to learn more about dark matter at the moment as it seems to be one of the biggest mysteries we're currently looking into from what I've seen. Any suggestions on good reading relating to it? I'm guessing most of it is heavy in theory without much matter-of-fact speaking but it's really interest stuff. To think there's so much out there yet we only know of it's existence through it's affects on other matter.

[M16]

I unfortunately don't know much about dark matter or dark energy off-hand, but my next research paper is on a topic called WIMPS (weakly interacting massive particles). Astronomers classify dark matter as some of these WIMPS. If you're looking for a good read into general relativity, time, etc., I would recommend The Universe in a Nutshell by Dr. Stephen Hawking. It's still moderately scientific, but he does a much better job of putting the theories into common terminology than most other authors out there.

[Heartless Angel]

Universe in a Nutshell was a great book, we used that alot in the last physics class I took. One of the only books I bought for school that I didn't turn around and sell when I was done with it. I've always been fascinated by Hawking's theories. Einstein's as well.

[Rhaps]

I've heard loosely about the Big Rip theory? Something to do with Dark Matter speeding up or slowing down something, eventually causing the universe to do a reverse Big Bang.
Anyone know anything else on that? I' have no more information.

[Trodorne]

so why not move through vasts amount of space by creating the proverbial nutcracker and re arrange space to cross a shorter distance. i got the duct tape when you all are ready.

[Rhaps]

Something in my instict tells me that if we try to speed up the theoretical Big Rip we could do some very very bad things to the cosmos.