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This newly detected neutron star is 333,000 times the mass of the Earth and 2.17 times the mass of the sun. But the star is only about 15 miles across. This is

This newly detected neutron star is 333,000 times the mass of the Earth and 2.17 times the mass of the sun. But the star is only about 15 miles across. This is close to the limit of how much mass a compact object can contain before it crushes itself into a black hole.

Gibbon1 7y ago
> This is close to the limit of how much mass a compact object can contain before it crushes itself into a black hole. Obviously it's time for bed because reading this makes me want to toss a quarter in it to see what happens.
- arethuza 7y ago
  Assuming you are starting from orbit wouldn't you have to give that coin quite a "toss" to get it to change its orbit so as to hit the surface? No atmosphere to help...
  - saagarjha 7y ago
    Not if you’re far enough away.
- sidcool 7y ago
  It would get shred to fundamental particles/waves. Then its electrons would fuse inside the nucleus to form a neutron gravy.
- GlobalFrog 7y ago
  I'm curious as well, for example to imagine how the event would unfold, as it would not be the direct remnant of a supernova. For an observer, would the neutron star seem to just disappear? Where would be the horizon and what would it look like as it suddenly appears?
  - ekimekim 7y ago
    I'm not a physicist, but I _think_ to my understanding what you would see is a collapse that would slow down and get more and more red-shifted, as the photons from the collapse take longer and longer to get to you (and are robbed of more and more energy, hence the red-shift). So what you would see is more of a slow fadeout as the object shrinks and gets redder and dimmer, until you can't see anything at all. In the limit as the object gets smaller and the photons get dimmer, you end up with something that emits no light and is the size of the black hole silouette.
    - mnw21cam 7y ago
      Saying that's what you would see is a bit like saying that if you push something it will keep moving forever. It's the physicist's answer, assuming ideal conditions. In reality, the initial collapse probably won't include all the mass of the object, including any dust or gas orbiting nearby it. So your lovely "fading from sight" black hole will be there, but obscured by the raging maelstrom (always wanted to use that word) of material now circling the plug-hole around it and heated to $DEITY knows what temperature.
- imvetri 7y ago
  ill throw equal quantity of vacuum to see if it counters your quarter :D
Aaargh20318 7y ago
> the star is only about 15 miles across According to the article it's 30 kilometers across. No need to incorrectly convert it to some medieval unit of measurement.
- romaaeterna 7y ago
  1. Miles are Roman, not Medieval. 2. What would be medieval would be a superstitious reaction to units of measurement as if they were purity religion cult signifiers rather than simple rational concepts to be converted between at will, depending on the task at hand.
  - mcbits 7y ago
    The "correct" conversion to (modern) miles would be 20, both because 30 has only one significant digit and because it makes more sense to round 18.x to 20 than to 15.
    - johnr2 7y ago
      > The "correct" conversion to (modern) miles would be 20 In nautical miles it would be closer to 15 ;-)
  - Aaargh20318 7y ago
    > Miles are Roman, not Medieval English miles aren't. Also, the conversion wasn't done correctly, there was no need to convert it al all, and SI units are the preferred unit of measurement in science.
    - deleted 7y ago
      [deleted]
    - romaaeterna 7y ago
      Who do you think ruled Britain until 410AD and give the English their mile, which is simply the word for "1000" in Latin? And I think that the press release is in error here. There was no radius measurement proposed in the Nature Astronomy paper. However, the radius in the press release is far to large. See: https://i.imgur.com/Y34OspJ.png https://i.imgur.com/Y34OspJ.png (From https://arxiv.org/pdf/1603.02698.pdf https://arxiv.org/pdf/1603.02698.pdf) Something on the order of 6-10 miles for a 2.14 M neutron star is much more appropriate. Notice that this measurement may rule out some of our models (mostly the gray lines on the left of the chart) that don't predict neutron stars this massive.
PopeDotNinja 7y ago
Imagine a far future game where bored teenagers grab the family spaceship, find a neutron star just below the blackhole limit, and throw things into it until it makes the switch. How fun would that be?!
- imvetri 7y ago
  ok. black hole and neutron star are between a silver line. I understand the idea of switch you spoke about. throw void into black hole (becomes neutron star) throw little piece of black hole into neutron star (becomes black hole) aah. little theory. blackhole mass can be used to convert neutron star to a blackhole. A balance between blackhole and neutron star.
  - hvidgaard 7y ago
    You can turn a neutron star into a black hole, but you cannot turn a black hole into anything else, only make them bigger.
- ars 7y ago
  You couldn't actually do that. Time dialation means the thrown object would never actually hit the neutron star from your POV and the black hole would never form.
SiempreViernes 7y ago
They actually measured a mass of 2.14

Gibbon1 7y ago

> This is close to the limit of how much mass a compact object can contain before it crushes itself into a black hole. Obviously it's time for bed because reading this makes me want to toss a quarter in it to see what happens.

arethuza 7y ago
Assuming you are starting from orbit wouldn't you have to give that coin quite a "toss" to get it to change its orbit so as to hit the surface? No atmosphere to help...
- saagarjha 7y ago
  Not if you’re far enough away.
sidcool 7y ago
It would get shred to fundamental particles/waves. Then its electrons would fuse inside the nucleus to form a neutron gravy.
GlobalFrog 7y ago
I'm curious as well, for example to imagine how the event would unfold, as it would not be the direct remnant of a supernova. For an observer, would the neutron star seem to just disappear? Where would be the horizon and what would it look like as it suddenly appears?
- ekimekim 7y ago
  I'm not a physicist, but I _think_ to my understanding what you would see is a collapse that would slow down and get more and more red-shifted, as the photons from the collapse take longer and longer to get to you (and are robbed of more and more energy, hence the red-shift). So what you would see is more of a slow fadeout as the object shrinks and gets redder and dimmer, until you can't see anything at all. In the limit as the object gets smaller and the photons get dimmer, you end up with something that emits no light and is the size of the black hole silouette.
  - mnw21cam 7y ago
    Saying that's what you would see is a bit like saying that if you push something it will keep moving forever. It's the physicist's answer, assuming ideal conditions. In reality, the initial collapse probably won't include all the mass of the object, including any dust or gas orbiting nearby it. So your lovely "fading from sight" black hole will be there, but obscured by the raging maelstrom (always wanted to use that word) of material now circling the plug-hole around it and heated to $DEITY knows what temperature.
imvetri 7y ago
ill throw equal quantity of vacuum to see if it counters your quarter :D

Aaargh20318 7y ago

> the star is only about 15 miles across According to the article it's 30 kilometers across. No need to incorrectly convert it to some medieval unit of measurement.

romaaeterna 7y ago
1. Miles are Roman, not Medieval. 2. What would be medieval would be a superstitious reaction to units of measurement as if they were purity religion cult signifiers rather than simple rational concepts to be converted between at will, depending on the task at hand.
- mcbits 7y ago
  The "correct" conversion to (modern) miles would be 20, both because 30 has only one significant digit and because it makes more sense to round 18.x to 20 than to 15.
  - johnr2 7y ago
    > The "correct" conversion to (modern) miles would be 20 In nautical miles it would be closer to 15 ;-)
- Aaargh20318 7y ago
  > Miles are Roman, not Medieval English miles aren't. Also, the conversion wasn't done correctly, there was no need to convert it al all, and SI units are the preferred unit of measurement in science.
  - deleted 7y ago
    [deleted]
  - romaaeterna 7y ago
    Who do you think ruled Britain until 410AD and give the English their mile, which is simply the word for "1000" in Latin? And I think that the press release is in error here. There was no radius measurement proposed in the Nature Astronomy paper. However, the radius in the press release is far to large. See: https://i.imgur.com/Y34OspJ.png https://i.imgur.com/Y34OspJ.png (From https://arxiv.org/pdf/1603.02698.pdf https://arxiv.org/pdf/1603.02698.pdf) Something on the order of 6-10 miles for a 2.14 M neutron star is much more appropriate. Notice that this measurement may rule out some of our models (mostly the gray lines on the left of the chart) that don't predict neutron stars this massive.

PopeDotNinja 7y ago

Imagine a far future game where bored teenagers grab the family spaceship, find a neutron star just below the blackhole limit, and throw things into it until it makes the switch. How fun would that be?!

imvetri 7y ago
ok. black hole and neutron star are between a silver line. I understand the idea of switch you spoke about. throw void into black hole (becomes neutron star) throw little piece of black hole into neutron star (becomes black hole) aah. little theory. blackhole mass can be used to convert neutron star to a blackhole. A balance between blackhole and neutron star.
- hvidgaard 7y ago
  You can turn a neutron star into a black hole, but you cannot turn a black hole into anything else, only make them bigger.
ars 7y ago
You couldn't actually do that. Time dialation means the thrown object would never actually hit the neutron star from your POV and the black hole would never form.

SiempreViernes 7y ago

They actually measured a mass of 2.14