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Possible Exploration to Europa in 2015
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42 / M / US
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Posted 6/27/07
^ cool...could you also let me know if my info was all jacked up please?
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37 / F / Fort Meade, MD
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Posted 6/27/07
Gravitational collapse in astronomy is the inward fall of a massive body under the influence of the force of gravity. It occurs when all other forces fail to supply a sufficiently high pressure to counterbalance gravity and keep the massive body in hydrostatic equilibrium.

Gravitational collapse is at the heart of structure formation in the universe. An initial smooth distribution of matter will eventually collapse and cause the hierarchy of structures, such as clusters of galaxies, stellar groups, stars and planets. For example, a star is born through the gradual gravitational collapse of a cloud of interstellar matter. The compression caused by the collapse raises the temperature until nuclear fuel ignites in the center of the star and the collapse comes to a halt. The thermal pressure gradient (leading to expansion) compensates the gravity (leading to compression) and a star is in dynamical equilibrium between these two forces.

Gravitational collapse of a star occurs at the end of its life time, also called the death of the star. When all stellar energy sources are exhausted, the interior of a star will undergo a gravitational collapse. In this sense a star is a "temporary" equilibrium state between a gravitational collapse at stellar birth and a gravitational collapse at stellar death. The end states are called compact stars.

*note not sure how accurate it is, since it's from wikipedia..
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42 / M / US
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Posted 6/27/07
I did some looking around on my own and came across a few science and astronomy sites. this is what they had to say:
"Since Jupiter is the biggest and most massive planet in the Solar System, it is not uncommon for one to think of it as a mini-star. However, Jupiter is still much too small to ignite and generate nuclear reactions. However, the interior of Jupiter is very hot nonetheless, probably around 20,000 K and is produced by the Kelvin-Helmholtz mechanism. This process is the generation of heat due to the gradual gravitational compression of the planet. The heat generated also is the cause of the turbulent conditions that are observed on the surface. Saturn and Neptune, also gas planets behave much in the same way Jupiter does in terms of heat generation but Uranus does not.

Looking back at the comparison between Jupiter and stars, one can see the obvious differences. Stars mainly are much more massive than planets, and in this case, Jupiter needs to be eighty times more massive in order to ignite like a star."


And

"Jupiter and Saturn have the peculiarity that they emits 2 and half times more energy than they receive from the Sun. Such energy derives from a slow gravitational contraction, which heats up their nucleus.
Besides, in their atmosphere the Hydrogen-Helium ratio is very similar to that of the Sun; this suggests that the two planets be two "missed stars": if they were more massive, the pressure and the temperature of the gas within them would be sufficient to trigger the thermonuclear reactions and they would become stars."


about Gravitational Compression:

"Gravitational Collapse

The source of the energy for star formation is gravitational collapse - this collapse must provide enough energy to heat the gas of the protostar to the ignition point of hydrogen fusion, some 15 million Kelvins. Knowledge of the mass and distribution of the gas cloud permits some fairly detailed modeling, because half of the energy from gravitational collapse goes into kinetic energy according to the virial theorem.

The concept of the Jean's Mass as the critical mass for collapse into a star is an important concept."


Kinds of gravitational contraction :

* dark cloud gravitational contraction
* iron core of supernova gravitational contraction
* star gravitational contraction

"By using virial theorem, Helmholtz and Kelvin showed that the contraction of a bound self-gravitating system must be accompanied by release of radiation energy irrespective of the details of the contraction process. This happens because the total Newtonian energy of the system EN (and not just the Newtonian gravitational potential energy EgN) decreases for such contraction. In the era of General Relativity (GR) too, it is justifiably believed that gravitational contraction must release radiation energy. However no GR version of (Newtonian) Helmholtz- Kelvin (HK) process has ever been derived. Here, for the first time, we derive the GR version of the appropriate virial theorem and Helmholtz Kelvin mechanism by simply equating the well known expressions for the gravitational mass and the Inertial Mass of a spherically symmetric static fluid. Simultaneously, we show that the GR counterparts of global ``internal energy'', ``gravitational potential energy'' and ``binding energy'' are actually different from what have been used so far. Existence of this GR HK process asserts that, in Einstein gravity too, gravitational collapse must be accompanied by emission of radiation irrespective of the details of the collapse process. Consequently, all studies of strictly adibatic gravitational collapse are only of academic interest.
Comment: Minor corrections, maiden derivation of proper GR virial theorem, shows there is no strict adiabatic collapse."


so that clears some things up about gravitational collapse and whether or not it is even possible for Jupiter to become a star.

uhmmm...wow...sorry i strayed from the topic on such a grand scale
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37 / F / Fort Meade, MD
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Posted 6/28/07
^ LOL.. i'll say ya strayed!

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24 / M / next to my pc
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Posted 6/28/07
wow i am completely lost (i am guessing here but does it show how the ratio of nitrogen and hydrogen and the heat could cause the planet to turn into a star if it was larger)
and yes i wanna see little squishy aliens its better than out of space germs
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37 / F / Fort Meade, MD
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Posted 6/28/07
what it's saying (correct me if i'm wrong act) that if a planet, such as Jupiter or Saturn aquires more mass... ie more space dust collects, the gravitational pull would be so strong that it would compress those atoms within the core of the planets and cause a fusion to begin, ie the birth of a star.

*note i'm at work, so i didn't have any notes or Texts to refer from, so i could be completely off base here.
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Posted 6/29/07
o... i get it now (i was not of the mark by much any way) its is not that much of a complicated subject , in fact it seems quite simple now.

on the europa subject i believe we have got mostly alll the information about it
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Posted 6/29/07
Space exploration, beyond the study of the moon and sun is a waste of money, billions of dollars just to get some rocks and pictures, could use that money for starving kids, homeless, and elderly

the only things worth investing money into is studying earth's atmosphere and the sun, so we could atleast stop fucking up our atmosphere
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37 / F / Fort Meade, MD
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Posted 6/29/07
:::sigh::::
I've said this before, and I"ll say it again:
Our atmosphere is not fucked up.
Humans are not responsible for any major changes in the atmosphere.
Global warming is a naturally occuring thing that happens every few million years. (see graph on my profile, under pictures)

Ok, to the other things.
Space exploration is the only way we will ever be able to discover the secrets to our world. To understand the principles of the universe helps humans understand the principles at work on our own planet.
Space exploration is important because of the millions of possible threats to our planet. Near misses and asteriod collisions for example.
Space exploration is also important, because some day we might just need to get off this rock (maybe because our sun will die? :::note the sarcasm!:::) And it might be nice to have a place to go.
As for the starving people and poverty on earth.
WHO GIVES A FUCK! <---not sympathetic to poverty nor idiots
If a person can't work their ass off to feed themselves or thier family, they DESERVE to die.
No one should get handouts.
Welfare is rediculous (sp). I hate the whole idea of welfare!
There are plenty of ways to make money or to support yourself and your family.
I've been homeless, I know!
I worked my ass off, and now i'm makin bank.
so DON'T give me any shit about poverty and hunger. those people are just stupid.

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Posted 6/29/07

Dusterbayala wrote:

:::sigh::::

As for the starving people and poverty on earth.
WHO GIVES A FUCK! <---not sympathetic to poverty nor idiots
If a person can't work their ass off to feed themselves or thier family, they DESERVE to die.
No one should get handouts.
Welfare is rediculous (sp). I hate the whole idea of welfare!
There are plenty of ways to make money or to support yourself and your family.
I've been homeless, I know!
I worked my ass off, and now i'm makin bank.
so DON'T give me any shit about poverty and hunger. those people are just stupid.


some of that stuff was quite ignorant what about the people in Africa who have to endure slavery and starvation because they were BORN in to poverty, and are forced to kill to be able to survive otherwise there families would be butchered and raped.
Benefits only happens in countries that can affords it and if you are in a rich country you should have no real excuses to be poor and benifites should be given because the future of the children should not be destroyed because the were to poor to educate there children or needed them to make money


BUT space exploration is not a waste of money because we (man kind) may one day have to leave earth and we need to know how to avoid damaging earth because if we do not then problems may occur

and you both were wrong and were going to the extremes about the subject.



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37 / F / Fort Meade, MD
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Posted 6/29/07
^I assumed the previous person was talking about non third world countries.
Apparently I assumed wrong.

However - "some of that stuff was quite ignorant what about the people in Africa who have to endure slavery and starvation because they were BORN in to poverty, and are forced to kill to be able to survive otherwise there families would be butchered and raped."
Sucks to be them. I'm still no changing my views on it, however. If they can't figure out how to get away, better themselves, then fine... Die. I don't care. I'm not going to support sending my money and spending my time on people who can't even help themselves.
If you are born into poverty, and Choose to have a family, that's your own problem when they start using that to control you, you gave them that.
If you are so weak as to allow someone to control you like that, then.. i'm sorry... but BYE!
I would rather die, than to let someone control me or my family.

***Back on topic.
We can also learn from space exploration how life came to earth. the more knowledge we learn, the clearer the picture becomes. Think of how ignorant people were about science 100 years ago. Look at what space exploration has given us!
Computers that don't take up a whole room, Cell phones, etc etc.

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24 / M / next to my pc
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Posted 6/29/07
I believe you are right about space exploration thing but it is not as simple as you make it out to be (getting away and repelling the oppressors), how would you get away ? how


would you repel an army of oppressor on your own ?

If you do not have knowledge how will we feed the inquisitive mind thats one of the reasons for space exploration
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37 / F / Fort Meade, MD
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Posted 6/29/07
No, I would die. Happily.

**on topic

Humans have insatiable curiousity, and space exploration is very vast. Possibly we can unlock the keys to space/time (someday) and be able to do so many vast things, it's insane if you really think about it.
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Posted 6/29/07
what about the hotel and space program on the moon (earths moon) what has happened to that because i have not heard of that since ages (2000) it sounded real ambitous
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37 / F / Fort Meade, MD
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Posted 6/29/07
Through the work of the NASA Exploration Team (NExT), a staging area at the Earth-Moon Lagrange Point, L1, is now being advocated.

This "Gateway location" at L1 - capable of being occupied from time to time by human crews -- is a possible way to return to the Moon, Cooke said. Also, this Gateway can be used to build-up, repair and service super-observatories that are positioned at the Earth-Sun Lagrange Point, L2.



I don't think it's not a go anymore, i just think the news media doesn't jump all over it like it used to..

**info taken from Space.com
http://www.space.com
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