- #1
Vincent Vega
- 42
- 0
Is there anything in the observable universe that weighs more? 1 teaspoon = billion tons
Neutron star: heaviest teaspoon of matter
- Context: Undergrad
- Thread starter Vincent Vega
- Start date
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- Tags
- Matter Neutron Neutron star Star
Click For Summary
Discussion Overview
The discussion revolves around the density of neutron stars and comparisons with other astronomical objects, particularly black holes. Participants explore theoretical aspects of neutron stars, their formation, and the implications of their extreme density, as well as the nature of black holes.
Discussion Character
- Exploratory, Technical explanation, Debate/contested
Main Points Raised
- One teaspoon of neutron star material is suggested to weigh around a billion tons, raising questions about the heaviest matter in the universe.
- Neutron stars are described as extremely dense, with a density of approximately 6.65 * 10^14 g/cm^3, supported by neutron degeneracy pressure rather than fusion.
- Some participants propose that quark stars might be denser than neutron stars, although this remains speculative without observational evidence.
- Black holes are mentioned as having theoretically infinite density, but their singularity is not well understood.
- One participant notes the extreme gravitational effects of neutron stars, such as the high impact speed of objects falling onto them and the energy released during such events.
- Another participant suggests that supermassive black holes could have higher density, but they question the rate at which such black holes would consume stars, indicating a potential overestimation.
- Clarifications are made regarding the nature of black holes, emphasizing that they do not "suck" objects in the way often portrayed.
Areas of Agreement / Disagreement
Participants express differing views on the density comparison between neutron stars and black holes, with some agreeing on the theoretical aspects while others challenge specific claims about accretion rates and the nature of black holes. The discussion remains unresolved regarding the absolute densest matter in the universe.
Contextual Notes
Some assumptions about the nature of black holes and neutron stars are not fully explored, and the discussion includes speculative elements regarding quark stars and the behavior of supermassive black holes.
- #2
Allday
- 164
- 1
hey Vega,
the matter in a neutron star is very (very very very) dense as you've grasped. Current theory explains neutron stars something like a giant nucleus, one that has a radius of about 10 km. (Actually the density of a neutron star is roughly 6.65 * 10^14 g/cm^3 while that in a typical nuclues is 'only' 2.3 * 10^14 g/cm^3). The star is being supported against gravitational collapse not by internal fusion like normal stars but by neutron degeneracy pressure. In plain english neutrons are a type of particle called fermions which don't like to be in the same place as other fermions so they exert a pressure if you bring them close together.
I don't think there are many things that could be denser because the nuetrons in the star are in the most closely packed configuration they can be in. I believe there are some speculative theories of quark stars where the individual neutrons dissolve into a sea of quarks, but there is no observational evidence that I am aware of. Also you have black holes which theoretically have infinite densities, but there is no theory that works well when trying to describe the singularity of a black hole.
Here are some other extreme facts about neutron stars
an object dropped from a height of 1m above the surface of a typical neutron star would impact the surface traveling at 4.3 million mph. that's one hell of a ride.
im kind of rambling here because its late, but another interesting thing is that the gravitational potential energy liberated when an object falls onto a neutron star is greater than the amount of energy one would liberate through the fusion of hydrogen atoms. ie throwing a chunk of hydrogen onto a nuetron star and collecting the energy that is radiated on the way down is a more efficient way to get energy than nuclear fusion!
hope your mind is warped
gabe
the matter in a neutron star is very (very very very) dense as you've grasped. Current theory explains neutron stars something like a giant nucleus, one that has a radius of about 10 km. (Actually the density of a neutron star is roughly 6.65 * 10^14 g/cm^3 while that in a typical nuclues is 'only' 2.3 * 10^14 g/cm^3). The star is being supported against gravitational collapse not by internal fusion like normal stars but by neutron degeneracy pressure. In plain english neutrons are a type of particle called fermions which don't like to be in the same place as other fermions so they exert a pressure if you bring them close together.
I don't think there are many things that could be denser because the nuetrons in the star are in the most closely packed configuration they can be in. I believe there are some speculative theories of quark stars where the individual neutrons dissolve into a sea of quarks, but there is no observational evidence that I am aware of. Also you have black holes which theoretically have infinite densities, but there is no theory that works well when trying to describe the singularity of a black hole.
Here are some other extreme facts about neutron stars
an object dropped from a height of 1m above the surface of a typical neutron star would impact the surface traveling at 4.3 million mph. that's one hell of a ride.
im kind of rambling here because its late, but another interesting thing is that the gravitational potential energy liberated when an object falls onto a neutron star is greater than the amount of energy one would liberate through the fusion of hydrogen atoms. ie throwing a chunk of hydrogen onto a nuetron star and collecting the energy that is radiated on the way down is a more efficient way to get energy than nuclear fusion!
hope your mind is warped
gabe
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- #3
Vincent Vega
- 42
- 0
It is... my mind that is. That's pretty narly info!
Last edited:
- #4
whiteholes
- 27
- 0
What has density than a neutron star? Hmmm, that would be a super massive black hole in a very large galaxy. It should be sucking in millions of stars per second!
- #5
Allday
- 164
- 1
white holes said:
yeah i would agree you could say the density is higher (infinite), but you overestimated the accretion rate a little there white hole. Say we had a galaxy with 10 trillion stars in it (a large over estimate) then if they were disappearing at the rate of a million per second the whole galaxy would be swallowed in ten million seconds or about 116 days. galaxies last a little longer than that.
- #6
tribdog
- 768
- 17
and black holes don't really suck things in like that. If our sun suddenly turned into a black hole we wouldn't even notice it, other than it would stay nighttime and get really cold. Our orbit would be the exact same.
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