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Went to the doctor today who told me I have a respiratory infection and that I can't leave the house till Friday. Which sucks seeing how I have to work and nobody will answer the damn phone. The doctor also gave me a bunch of samples and when I walked out into the waiting room I looked like I had just robbed the medicine cabinet for samples, looked like candy stuffed in my pockets etc.
Okay so I watched this show on National Geographic called Journey to the edge of the Universe. So soem questions:
I read that the Andromeda Galaxy will collide with the milky way and apparently stars could be thrown out as the two merge. Can a solar system exist outside of a galaxy, like outside of the milky way and just be in space?
Black holes, not even light can escape. So what happens if two or more black holes meet? Also what is the shape of a black hole, could you go under, or on the other side of a black hole and not be affected?
Does a Sun ever cease to exist, after it dies is it possible that it is no longer there or do stars always leave a trace even after they cease to exist to create energy?
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The sun will be allright for a couple of billion years. After that it grows into a red giant with much more output that will vaporise all the water. Earth will be uninhabitable.
If the sun or the earth collides with a star its all over. A near miss will destabilize the orbits around the sun and earth will get to close to the sun or get into an eliptical orbit or slingshot into deep space.
If the whole solarsystem ends up outside the milkyway there is no problem if the sun is the same and the earth orbit around it is the same. We will have far less stars in the sky. Maybe the core of the new combined milkyway can be seen at night. Travel to other stars will be even more problematic then it is now.
Rough sketch of how I think it will be.
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On the subject of black holes meeting a simulation was done of such an event: http://www.newscientist.com/article/dn9012
Andromeda will supposedly collide with us in 3 billion years which means for us that the death of the sun in 5 billion years is irrelevant. I think it's probably possible that a solar system could exist outside a galaxy but I think it's very likely that the planets will be ripped apart from it in some fashion and lost but I'm no astronomer so I can't say for sure.
When a star there is stuff that's left behind: http://en.wikipedia.org/wiki/Life_of_a_star#Stellar_remnants
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On December 11 2008 07:17 {CC}StealthBlue wrote:
Went to the doctor today who told me I have a respiratory infection and that I can't leave the house till Friday. Which sucks seeing how I have to work and nobody will answer the damn phone. The doctor also gave me a bunch of samples and when I walked out into the waiting room I looked like I had just robbed the medicine cabinet for samples, looked like candy stuffed in my pockets etc.
Okay so I watched this show on National Geographic called Journey to the edge of the Universe. So soem questions:
I read that the Andromeda Galaxy will collide with the milky way and apparently stars could be thrown out as the two merge. Can a solar system exist outside of a galaxy, like outside of the milky way and just be in space?
Black holes, not even light can escape. So what happens if two or more black holes meet? Also what is the shape of a black hole, could you go under, or on the other side of a black hole and not be affected?
Does a Sun ever cease to exist, after it dies is it possible that it is no longer there or do stars always leave a trace even after they cease to exist to create energy?
Doesn't having a solar system make something a galaxy? Like, if there were a solar system floating in space, that solar system's space would be a galaxy?
If two black holes meet, the bigger black hole will eat the small black hole. Unless, the small black hole as a greater force pulling it (assuming not all black holes pull in at the same speed), then the big black hole will go into small black hole. Shape of black hole is like a 3d spherical object type of thing or something. Space from all sides of it are sucked into this 3d object into the focal point. you can go under it and above it and around it, but if you get too close, you will get sucked in.
A sun will cease to exist, but not completely. After it explodes, I think the energy released from the explosion will either decimate all the mass into really tiny particles that get spread into the space. Or, the mass gets burned by the great amount of energy released, so all the mass gets converted into heat or energy (so nothing will exist, no trace).
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I don't know :O But apparently 'plasma' as a rocket propulsion system is gonna be a reality fairly soon. On discovery channel the guy was saying it was like 'the 4th state of matter, such that exists naturally in lightning'. So like... solid... liquid... gas... plasma... :S
Maybe humanity can last a million years if we just develop a way to reliably travel ultra long distances thru space  This plasma stuff won't do it initially though... They said using it, it would make getting a manned rocketship to Mars realistic, but who knows how useful that will really be... We need a way to get the rocket ship, and tonnes and tonnes of nuclear waste and gunk to Mars
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United States24753 Posts
On December 11 2008 07:42 Chef wrote:
I don't know :O But apparently 'plasma' as a rocket propulsion system is gonna be a reality fairly soon. On discovery channel the guy was saying it was like 'the 4th state of matter, such that exists naturally in lightning'. So like... solid... liquid... gas... plasma... :S
Yeah that's the textbook definition of plasma I learned in middle school. I'm curious how they are going to utilize it so I guess I will research it.
Maybe humanity can last a million years if we just develop a way to reliably travel ultra long distances thru space This plasma stuff won't do it initially though... They said using it, it would make getting a manned rocketship to Mars realistic, but who knows how useful that will really be... We need a way to get the rocket ship, and tonnes and tonnes of nuclear waste and gunk to Mars
I think propulsion is only one of several major problems with interstellar travel.
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Yeah, but it's one of the biggest ones. The other is the immense amount of training and funds needed for the astronauts and the rocket, and the fact that it isn't even close to guaranteed that it won't blow up and kill everyone inside. Hard to find people so skilled who want to risk their lives too I think
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3 Billion years? We should get people on that. I mean... to survive we'll need to be in a whole different galaxy. Intergalactic travel is a lot of research away...
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An interesting thing about stars after they die, which I just learned last week, is that, since the swirling plasma of the star can create a huge magnetic field, this magnetic field can actually continue to exist for a long time after the star has died.
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On December 11 2008 07:48 micronesia wrote:Show nested quote +Maybe humanity can last a million years if we just develop a way to reliably travel ultra long distances thru space This plasma stuff won't do it initially though... They said using it, it would make getting a manned rocketship to Mars realistic, but who knows how useful that will really be... We need a way to get the rocket ship, and tonnes and tonnes of nuclear waste and gunk to Mars I think propulsion is only one of several major problems with interstellar travel.
care to list any of the others out of interest? i always am interested in your input in these situations
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I'm currently reading a book called The Black Hole War, it's a pretty interesting read, you should look into it. Basically two black holes could meet each other in space and they would merge into one giant black hole. And yes according to Einstein nothing can travel faster then light, therefore, nothing can escape a black hole.
The book I'm reading is pretty much based around whether information is lost in black holes forever or not. If information is lost (according to Hawking) then that pretty much defies about 200 years of physics. The guy who wrote the book is trying to prove Hawking wrong. Annnnyways according to the guy who wrote the book (Leonard Susskind) black holes get smaller and smaller, but only if they aren't consuming anything (so when no matter is going into them). Once an object, or beam of light, or anything passes the black holes horizon it cannot overcome the black holes gravitational force.
Black holes appear to be circular, and no you can't "survive" a black hole. Once you're past the horizon and hit the singularity you are basically stretched forever and ever until you're one molecule thick, and all the molecules in your body long. This is all pretty much theoretical at this point, like some scientists say that black holes are worm holes that can take you to other parts of the universe.
Also, I assume that a solar system can exist out of a galaxy, it's just that the infinitely dense black hole at the center of our galaxy pulls us and all other matter in the vicinity into a close proximity. The same is with Earth and our Sun on a much smaller scale.
After stars implode they become a white dwarf or if they're much larger a red dwarf. After red dwarfs squeeze so tight and hit a certain density they become a black hole. Back to the book I'm reading... If a black hole ever did shrink and shrink to the point where it disappeared (which can never happen, but maybe I'll explain later) then that's the point where the argument on whether all the information it sucked in over the year happens. Is the information lost forever? Is it spewed back out?
My take on the big bang is that a giant black hole sucked up all the matter in the universe over billions and possibly trillions of years, and eventually over more trillions of years it grew smaller and smaller. When it finally hit a Plank's Length (look it up) the black hole exploded, and viola the big bang.
I know that my post isn't very organized, I apologize, but I basically just word vomited. If you have any more questions just ask, I'll check in on this blog later...
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On December 11 2008 07:33 KaasZerg wrote:
The sun will be allright for a couple of billion years. After that it grows into a red giant with much more output that will vaporise all the water. Earth will be uninhabitable.
If the sun or the earth collides with a star its all over. A near miss will destabilize the orbits around the sun and earth will get to close to the sun or get into an eliptical orbit or slingshot into deep space.
If the whole solarsystem ends up outside the milkyway there is no problem if the sun is the same and the earth orbit around it is the same. We will have far less stars in the sky. Maybe the core of the new combined milkyway can be seen at night. Travel to other stars will be even more problematic then it is now.
Rough sketch of how I think it will be.
The sun isn't big enough/dense/have enough mass to become a red dwarf. It will become a white dwarf, but in the process it will become HUGE, eating up the Earth and I can't remember how far into the solar system, but basically it expands extremely fast
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On December 11 2008 08:00 GGQ wrote:
3 Billion years? We should get people on that. I mean... to survive we'll need to be in a whole different galaxy. Intergalactic travel is a lot of research away...
So is another inhabitable planet =P.
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On December 11 2008 07:40 GrayArea wrote:
If two black holes meet, the bigger black hole will eat the small black hole. Unless, the small black hole as a greater force pulling it (assuming not all black holes pull in at the same speed), then the big black hole will go into small black hole. Shape of black hole is like a 3d spherical object type of thing or something. Space from all sides of it are sucked into this 3d object into the focal point. you can go under it and above it and around it, but if you get too close, you will get sucked in.
More specifically they combine to form a single, larger black hole with the mass of both combined.
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Wow! I thought that humans are already inhabiting the Koprulo Sector... I guess I played to much starcraft campaigns..
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On December 11 2008 08:00 GGQ wrote:
3 Billion years? We should get people on that. I mean... to survive we'll need to be in a whole different galaxy. Intergalactic travel is a lot of research away...
If you consider the rate at which our technology is advancing I don't think we should be too worried about 3 billion years.
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United States24753 Posts
On December 11 2008 08:03 DhakhaR wrote:Show nested quote +On December 11 2008 07:48 micronesia wrote:Maybe humanity can last a million years if we just develop a way to reliably travel ultra long distances thru space This plasma stuff won't do it initially though... They said using it, it would make getting a manned rocketship to Mars realistic, but who knows how useful that will really be... We need a way to get the rocket ship, and tonnes and tonnes of nuclear waste and gunk to Mars I think propulsion is only one of several major problems with interstellar travel. care to list any of the others out of interest? i always am interested in your input in these situations
Using Newtonian mechanics, it takes a very long time to accelerate up to a speed sufficient for traveling to another star. It takes about the same amount of time to decelerate down to a suitable speed. For a quick example:
The closest star other than our Sun is about 4.2421 light years away. If we accelerated from rest at approximately the acceleration due to gravity (9.8 m/s^2) up to a top speed, and then decelerated at -9.8 m/s^2 to a stop just as we reached the destination, how long would it take? (The purpose of using 9.8 is that you would have simulated gravity on the spaceship. Going with a higher acceleration would probably make manning the ship difficult.)
d1 = d2 = D/2
d=vi*t+.5*a*t^2
d1 = .5 * 9.8 * t1^2
t1 = sqrt(d1/4.9)
D=vt
D = 3e8(m/s) * 4.2421(ly)*365.25(day/ly)*24(hour/day)*60(minute/hour)*60(second/minute) = 4.02e16 m
d1 = D/2 = 2.01e16 m
t1 = sqrt(2.01e16/4.9) = 64047176 seconds = 2.03 years
T = 4.06 years.
vf1 = 9.8*t1 = 627,662,325 m/s = 2.09 * c
So in other words, it would take 4.06 years to get there after reaching a top speed of 2778779588 m/s. This is bad because...
1) Burning an engine continuously for 4.06 years to get there, and another 4.06 to get back (let's say) is unfathomable. Most space travel is just coasting after building up speed at the beginning.
2) Traveling at speeds that fast are probably dangerous, even in space. 1 speck of dust hits your ship and gg.
3) You need to provide sustenance for the astronauts, fuel for the entire trip, and it becomes harder and harder to contact the ship as it gets further from the Earth. After all, it takes 4.2421 years for light to get from here to Proxima Centauri and that's about how long a transmission would take.
Of course... Newtonian Mechanics doesn't take something into account: Special Relativity. You can't travel more than 3e8 m/s according to modern theories (hence my note earlier about the top speed being 2.09 * c. In fact, in that model, the astronauts would get to the distant star faster than a radio signal that left Earth at the same time). First we need to accelerate to c, and then travel at c until we reach the braking point:
vf^2 = vi^2 + 2ad
(3e8)^2 = 2(9.8)d
d1 = 4591836734693878 m
d2 = d1 = 4591836734693878
d=vi*t+.5*a*t^2
4591836734693878=.5*9.8*t^2
t1 = t2 = 30612245 s
D-(d1+d2) = 4.02e16 - (2*4591836734693878) = 4.02e16 - 9183673469387756 = 31016326530612244 m
t = d/v = 31016326530612244/3e8 = 103387755 s
T = t1 + t2 + t3 + 2*30612245 + 103387755 = 164612245s = 5.22 years
So it would take even longer with a speed limit. However, if you study special relativity, you will see that traveling near the speed of light poses many challenges. Time dilates, meaning when one second passed for the astronauts, several would for us. I think studying special relativity would be required to further analyze this. BTW I did all this in MS calculator so I probably goofed somewhere.
edit: fixed a few errors
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A really interesting read on end of universe scenarios: www.exitmundi.nl
On the subject of black holes meeting..Since black holes have an infinitesimal density, would it be neutrality? Or what? Size isn't a factor in this equation, I think.
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@micronesia: You probably already know this, but while SR adds extra challenges, it opens up another possibility too. Because of the time dilation, a trip which would be very long for observers on earth would only take a short time for the astronauts. So, in theory an astronaut could travel one million light years in only one year of "travel time".
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EPT
