Is it possible...a blackhole......
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Simply put, white dwarfs have a mass which is less than our Sun. When they are going to "die", they used up their helium and hydrogen. There is some carbon left, but they are not hot enough to burn the carbon. So, whatever is leftover is being blown off, leaving a white stuff called white dwarf. Note that even if Earth is not destroyed by humans or any other disaster, when the Sun becomes a red star, it will be Doomsday.Originally posted by wonderamazement:Ok...
Introduction to White Dwarfs:
Where a star ends up at the end of its life depends on the mass, or amount of matter, it was born with. Stars that have a lot of mass may end their lives as black holes or neutron stars. Low and medium mass stars will become something called a white dwarf. A typical white dwarf is half as massive as the Sun, yet only slightly bigger than the Earth. This makes white dwarfs one of the densest forms of matter, surpassed only by neutron stars.Medium mass stars, like our Sun, live by burning the hydrogen that dwells within their cores, turning it into helium. This is what our Sun is doing now. The heat the Sun generates by its nuclear fusion of hydrogen into helium creates an outward pressure. In another 5 billion years, the Sun will have used up all the hydrogen in its core.
This situation in a star is similar to a pressure cooker. Heating something in a sealed container causes a build up in pressure. The same thing happens in the Sun. Although the Sun may not strictly be a sealed container, gravity causes it to act like one, pulling the star inward, while the pressure created by the hot gas in the core pushes to get out. The balance between pressure and gravity is very delicate.
When the Sun runs out of hydrogen to burn, gravity temporarily tips the balance, and the star starts to collapse. But compacting a star causes it to heat up again and it is able burn what little hydrogen remains in a shell wrapped around its core.
This burning shell of hydrogen will give our Sun the energy to expand again. When this happens, our Sun will become a red giant; it will be so big that Mercury will be completely swallowed!
When a star gets bigger, its heat spreads out making its overall temperature cooler. But over time, the core temperature of our red giant Sun will increase again until it's finally hot enough to burn all the stored up helium it created in its former incarnation. Eventually, it will transform the helium into carbon and other heavier elements. The Sun will only spend one billion years as a red giant, as opposed to the nearly 10 billion it spent busily burning hydrogen.
We already know that medium mass stars, like our Sun, become red giants. But what happens after that? Well, our red giant Sun is still eating up helium and cranking out carbon. But when it's finished its helium, it isn't quite hot enough to be able to burn the carbon it created. What now?
Our Sun isn't hot enough to ignite the carbon it its core, so the only thing it can do is succumb to gravity again. When the core of the star contracts, it causes a release of energy that makes the envelope of the star expand. Now the star has become an even bigger giant than before! Our Sun's radius has become larger than Earth's orbit! The Sun is not very stable at this point and loses mass similar to how a boiling kettle loses water by releasing steam. This continues until the star finally blows its outer layers off in a gust of superwind. The core of the star, however, remains intact, and becomse exposed to the outside universe -- this is the white dwarf. This leaves behind a white dwarf surrounded by an expanding shell of gas in an object known as planetary nebula. They are called this because early observers thought they looked like the planets Uranus and Neptune. There are some planetary nebulae that can be viewed through a backyard telescope. In about half of them, the central white dwarf can be seen using a moderate sized telescope.
Planetary nebulae seem to mark the transition of a medium mass star from red giant to white dwarf. Stars that are comparable in mass to our Sun will become white dwarfs within 75,000 years of blowing their envelopes. Eventually they, like our Sun, will cool down, radiating heat into space, fading into black lumps of carbon. It has taken 10 billion years, but our Sun has reached the end of the line and quietly become a black dwarf.
White dwarfs can tell us important things about the age of the universe. If we can estimate the time it takes for a white dwarf to cool into a black dwarf, that would give us a lower limit on the age of the universe and our galaxy. Because it takes billions of years for white dwarfs to cool, we don't think the universe is old enough yet for many, if any, white dwarfs to have become black dwarfs. This is why we want to learn more about white dwarfs. They could be an important key to understanding our universe. -
someone tell me more...
if not tell me where i can read up those interesting black hole stuffs/black dwarfs/white dwarfs/red star..
I'm very interested in unsolved science mystery, things like bermuda triangle too.. -
Library is a good place to start with. Read those books written for children to get basics. Then proceed to the adult's version, but adult's version very chim. You need to know a lot about Physics laws to know what they are talking about.Originally posted by FadeToBlack:someone tell me more...
if not tell me where i can read up those interesting black hole stuffs/black dwarfs/white dwarfs/red star..
I'm very interested in unsolved science mystery, things like bermuda triangle too..
For blackholes, read Stephen Hawking's books. Although his books are quite thick, it is very easy to understand, unlike other books. He also explains the Physics laws so that you don't have to borrow Physics books.
There's no black dwarfs by the way. Just red and white dwarfs.
Unsolved science mysteries books can also be found in the library. You can start from children books if you want to, but there is no need to. -
There's always the search engine.
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http://www.seasky.org/cosmic/sky7a01.html
This site is one of the best I have seen.
http://www.nasa.gov/
A simple site, suitable just for everyone.
http://groups.msn.com/astronow
This MSN group I joined is superb. Everything you want to know can be found here. There are also a lot of pictures, of which these pictures give you links for the explanation why this phenonmen happens.
http://groups.msn.com/Browse?CatId=299
See got interest you and join them. -
is it possible for an uneducated, unlearned man living 1400 years ago to be able to speak of the big bang, the planets in their orbits, the earth being round, the universe expanding, man going to outer space, the blackhole and other scientific facts unknown during that period?
where does he learn all that when even scientists dduring that time doesnt know all that?
Can it actually be the word of God?
Do you believe the universe will all come to an end one day?
I believe but a lesson taught to us Muslims from our holy Prophet Muhammad s.a.w. is to be fearful of the 'smaller' end of the world than the major one. The 'smaller' one he refers to as Death.
Verily Death will come unto us all & nothing, even as small as an atom, can escape it.
therefore, let us all be good to each other, be compassionate, be kind, be helpful, be generous, be respectful and live in peace & harmony. -
Humans can learn. So it is possible for a man to be uneducated and unlearned to know all these. There's something called observation by the way. Whether universe will end or not is still a topic that is under research and astronomers are still debating.Originally posted by hamirra:is it possible for an uneducated, unlearned man living 1400 years ago to be able to speak of the big bang, the planets in their orbits, the earth being round, the universe expanding, man going to outer space, the blackhole and other scientific facts unknown during that period?
where does he learn all that when even scientists dduring that time doesnt know all that?
Can it actually be the word of God?
Do you believe the universe will all come to an end one day?
I believe but a lesson taught to us Muslims from our holy Prophet Muhammad s.a.w. is to be fearful of the 'smaller' end of the world than the major one. The 'smaller' one he refers to as Death.
Verily Death will come unto us all & nothing, even as small as an atom, can escape it.
therefore, let us all be good to each other, be compassionate, be kind, be helpful, be generous, be respectful and live in peace & harmony. -
How could you hear the blackhole moving? There is vacuum in space and the sound can't spread in vacuum. Where from is it moving? Is it carrying its suitcase with it? How long will it stay when it arrives?Originally posted by wonderamazement:Heard that a blackhole is moving towards the milky way...... -
Hmm but by then...i think there shud be a way to pump gas to the sun?
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gravity is possibly the strongest force in the universe. It can tear the fabric of space time, so why not collapse a star?Originally posted by wonderamazement:What i mean is a blackhole is formed when the star dies, the nuclear fusion reactions stop because the fuel for these reactions gets burned up. At the same time, the star's gravity pulls material inward and compresses the core. As the core compresses, it heats up and eventually creates a supernova explosion in which the material and radiation blasts out into space. What remains is the highly compressed, and extremely massive,
core. The core's gravity is so strong that even light cannot escape -
light more powerful . i forget my physics teacher say wat if light go a little bit faster then the speed now then time will reverse or move faster.
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what he means is if u travel faster than light, technically speaking u can SEE the past, or rather, u will catch up with, and pass, the light from the past, hence u can "see" the past.Originally posted by Technomage:light more powerful . i forget my physics teacher say wat if light go a little bit faster then the speed now then time will reverse or move faster.
but while light allows u to see the past or even reverse time, gravity allows u to totally disregard the rules of time itself. Strong enough, it renders it irrelavent, it disrupts our known dimensions of time space. Besides, light cannot escape gravity either.
no. gravity is definately MUCH stronger than light. -
You can wish for that. The sun's core is so hot that if anything gets near it, it will turn into gaseous state instantly. That's the reason why you can't stay in Mercury or Venus. They are too near the Sun.Originally posted by wonderamazement:Hmm but by then...i think there shud be a way to pump gas to the sun? -
Ok, since you are entertaining me, why not tell me more about the pulsars and quasars while you at it.Originally posted by wonderamazement:Ok... Introduction to White Dwarfs:
Where a star ends up at the end of its life depends on the mass, or amount of matter, it was born with. Stars that have a lot of mass may end their lives as black holes or neutron stars. Low and medium mass stars will become something called a white dwarf. A typical white dwarf is half as massive as the Sun, yet only slightly bigger than the Earth. This makes white dwarfs one of the densest forms of matter, surpassed only by neutron stars.Medium mass stars, like our Sun, live by burning the hydrogen that dwells within their cores, turning it into helium. This is what our Sun is doing now. The heat the Sun generates by its nuclear fusion of hydrogen into helium creates an outward pressure. In another 5 billion years, the Sun will have used up all the hydrogen in its core.
This situation in a star is similar to a pressure cooker. Heating something in a sealed container causes a build up in pressure. The same thing happens in the Sun. Although the Sun may not strictly be a sealed container, gravity causes it to act like one, pulling the star inward, while the pressure created by the hot gas in the core pushes to get out. The balance between pressure and gravity is very delicate.
When the Sun runs out of hydrogen to burn, gravity temporarily tips the balance, and the star starts to collapse. But compacting a star causes it to heat up again and it is able burn what little hydrogen remains in a shell wrapped around its core.
This burning shell of hydrogen will give our Sun the energy to expand again. When this happens, our Sun will become a red giant; it will be so big that Mercury will be completely swallowed!
When a star gets bigger, its heat spreads out making its overall temperature cooler. But over time, the core temperature of our red giant Sun will increase again until it's finally hot enough to burn all the stored up helium it created in its former incarnation. Eventually, it will transform the helium into carbon and other heavier elements. The Sun will only spend one billion years as a red giant, as opposed to the nearly 10 billion it spent busily burning hydrogen.
We already know that medium mass stars, like our Sun, become red giants. But what happens after that? Well, our red giant Sun is still eating up helium and cranking out carbon. But when it's finished its helium, it isn't quite hot enough to be able to burn the carbon it created. What now?
Our Sun isn't hot enough to ignite the carbon it its core, so the only thing it can do is succumb to gravity again. When the core of the star contracts, it causes a release of energy that makes the envelope of the star expand. Now the star has become an even bigger giant than before! Our Sun's radius has become larger than Earth's orbit! The Sun is not very stable at this point and loses mass similar to how a boiling kettle loses water by releasing steam. This continues until the star finally blows its outer layers off in a gust of superwind. The core of the star, however, remains intact, and becomse exposed to the outside universe -- this is the white dwarf. This leaves behind a white dwarf surrounded by an expanding shell of gas in an object known as planetary nebula. They are called this because early observers thought they looked like the planets Uranus and Neptune. There are some planetary nebulae that can be viewed through a backyard telescope. In about half of them, the central white dwarf can be seen using a moderate sized telescope.
Planetary nebulae seem to mark the transition of a medium mass star from red giant to white dwarf. Stars that are comparable in mass to our Sun will become white dwarfs within 75,000 years of blowing their envelopes. Eventually they, like our Sun, will cool down, radiating heat into space, fading into black lumps of carbon. It has taken 10 billion years, but our Sun has reached the end of the line and quietly become a black dwarf.
White dwarfs can tell us important things about the age of the universe. If we can estimate the time it takes for a white dwarf to cool into a black dwarf, that would give us a lower limit on the age of the universe and our galaxy. Because it takes billions of years for white dwarfs to cool, we don't think the universe is old enough yet for many, if any, white dwarfs to have become black dwarfs. This is why we want to learn more about white dwarfs. They could be an important key to understanding our universe.
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Since you want to be entertained, I give you one website about pulsars and quasars. But first, do you understand what is neutron stars written in his reply? If not, research first.Originally posted by shadowlunar:Ok, since you are entertaining me, why not tell me more about the pulsars and quasars while you at it.
http://imagine.gsfc.nasa.gov/docs/science/know_l2/pulsars.html
http://starchild.gsfc.nasa.gov/docs/StarChild/universe_level2/quasars.html
How about a chim version to challenge you?
http://csep10.phys.utk.edu/astr162/lect/active/quasars.html -
technically, the side of Venus NOT facing the sun is freezing. The reason we can't stay on venus is aplenty, including an atmosphere that is both suffocating and corrosive, too high an atmospheric pressure etc.Originally posted by ndmmxiaomayi:You can wish for that. The sun's core is so hot that if anything gets near it, it will turn into gaseous state instantly. That's the reason why you can't stay in Mercury or Venus. They are too near the Sun. -
speaking of the Andromeda galaxy, whhen it colides with the milky way we will be able to see the 2 of them in our backyard!! even bigger and clearer than the moon ... imagine how close that will be!! Ripped of frm discovery chOriginally posted by abao:Most Galaxies have black holes near their centre, and our closest neighbouring galaxy, the Andromeda galaxy is heading towards the Milky Way. -
but i will take3 billion years to reach the milky way
will u live to see it?
Wikipedia:The Andromeda Galaxy is approaching the Milky Way at an average speed of about 140 kilometres per second; therefore it is one of the few galaxies to exhibit a blue shift. However, this doesn't mean it will collide with the Milky Way, since the galaxy's tangential velocity is unknown. But if it is on a collision course, the impact is predicted to occur in about 3 billion years. In that case the two galaxies will merge to form a giant elliptical galaxy. Such events are frequent among the galaxies in galaxy groups.
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Heeheheee...
This Blackhole topic reminds of our government the PAP....
heheheheheee.... -
I believe we ARE in the Milky Way.Originally posted by kenshin_himura:speaking of the Andromeda galaxy, whhen it colides with the milky way we will be able to see the 2 of them in our backyard!! even bigger and clearer than the moon ... imagine how close that will be!! Ripped of frm discovery ch -
Still have a long^30 time before this happens.Originally posted by kenshin_himura:speaking of the Andromeda galaxy, whhen it colides with the milky way we will be able to see the 2 of them in our backyard!! even bigger and clearer than the moon ... imagine how close that will be!! Ripped of frm discovery ch
Anyway, I won't be alive to see that, unless cloning techniques and genetic engineering techniques improve.
I don't want to live that long either. -
Hmmmm...what's the outcome after the collision???
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interesting... sooner or later we will be destroyed. there is our mister asteriod, n some other stone, the moon losing its pul on earth, etc. so many ways that we can die from any second. pretty surprise got ppl reply this post. from what i know, most ppl are not that interested in this sciece stuff. at least my fren don. btw when did discovery chn show that something is going collide? keep posting.
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Who knows....maybe we'll nuke each other..when the asteroids/blackhole comes we'll all be dead
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No need to know. We will be dead by then.Originally posted by wonderamazement:Hmmmm...what's the outcome after the collision???