The thread for space cadets!

[hobbsyoyo]

Our friendly neighborhood supergiant Betelgeuse is giving signs that it may go supernova according to the popular science press. I expect the hype is a bit overblown but it's a cool thing to think about as it would about as bright as the full moon if it did happen. We're far enough away that it should be harmless as well. Betelgeuse went from being the 9th-brightest stars to almost invisible to the naked eye over the last few months although it should be noted that as a variable star, it does that from time to time.

It is so large that even though it is 700 light years away, we've actually got pictures of it as a disc rather than a pinpoint of light.


And yes, it really is asymmetrical like that:

1988/9 UV HST images of Betelgeuse showing asymmetrical pulsations with corresponding spectral line profiles


Radio image from 1998 (pre-Harper) showing the size of Betelgeuse's photosphere (circle) and the effect of convective forces on the star's atmosphere

https://en.wikipedia.org/wiki/Betelgeuse

 

[Timsup2nothin]

Our friendly neighborhood supergiant Betelgeuse is giving signs that it may go supernova according to the popular science press. I expect the hype is a bit overblown but it's a cool thing to think about as it would about as bright as the full moon if it did happen. We're far enough away that it should be harmless as well. Betelgeuse went from being the 9th-brightest stars to almost invisible to the naked eye over the last few months although it should be noted that as a variable star, it does that from time to time.

It is so large that even though it is 700 light years away, we've actually got pictures of it as a disc rather than a pinpoint of light.


And yes, it really is asymmetrical like that:

1988/9 UV HST images of Betelgeuse showing asymmetrical pulsations with corresponding spectral line profiles


Radio image from 1998 (pre-Harper) showing the size of Betelgeuse's photosphere (circle) and the effect of convective forces on the star's atmosphere

https://en.wikipedia.org/wiki/Betelgeuse

Not to be a nitpick, but really this means that we are about to find out whether Betelgeuse exploded seven hundred years ago, or not.

 

[red_elk]

I read about that too, it may explode very soon, may be in mere couple of thousand years or so.

 

[Thorgalaeg]

I have not patience to wait so much. I want it to explode now!

 

[Lemon Merchant]

I have not patience to wait so much. I want it to explode now!

Keep in mind that a bunch of little xenomorphs will likely die as a result...

 

[Zkribbler]

Cotton-candy exoplanets discovered. https://edition.cnn.com/2019/12/19/world/cotton-candy-exoplanet-discovery-scn/index.html

The size of Jupiter, mass-wise the planets are a hundred times lighter.

 

[Timsup2nothin]

I have not patience to wait so much. I want it to explode now!

If it exploded the moment you typed that you'll never know.

 

[Thorgalaeg]

If it exploded the moment you typed that you'll never know.

Then i want it to explode 700 years ago.

 

[red_elk]

The Earth will be fine though. Even some people may survive.

 

[Thorgalaeg]

They will envy the dead.

 

[hobbsyoyo]

Keep in mind that a bunch of little xenomorphs will likely die as a result...

They were all fried long ago if they ever existed. Giant stars like Betelgeuse live hard, fast lives and are in and out in a flash. Life likely never developed in that system and if it did, it was probably wiped out when the star went into the supergiant phase and ate most of its planets.

 

[Thorgalaeg]

They were all fried long ago if they ever existed. Giant stars like Betelgeuse live hard, fast lives and are in and out in a flash. Life likely never developed in that system and if it did, it was probably wiped out when the star went into the supergiant phase and ate most of its planets.

I think supernovas are powerful enough to fry close solar systems a few LY away.

 

[Imaus]

They were all fried long ago if they ever existed. Giant stars like Betelgeuse live hard, fast lives and are in and out in a flash. Life likely never developed in that system and if it did, it was probably wiped out when the star went into the supergiant phase and ate most of its planets.

Which is why my first thought was 'maybe some artificial power sapped what it can from it and it went haywire'. Granted, that's the Orion's Arm influence talking.

 

[hobbsyoyo]

@Thorgalaeg
True but the average distance between stars is 5 to 10 light years. I don't think many get fried during the burst as at that distance.

Paging @uppi

 

[uppi]

Not to be a nitpick, but really this means that we are about to find out whether Betelgeuse exploded seven hundred years ago, or not.

Not to be a nitpick, but technically, "now" means a 1400 year long interval when talking about an even that occurs at a distance of 700 light years. The past begins when something moving at light speed could have hit us.

@Thorgalaeg
True but the average distance between stars is 5 to 10 light years. I don't think many get fried during the burst as at that distance.

Paging @uppi

To answer this, you need to have a definition of "fry". I'd say frying starts somewhere around where the supernova would be as bright as the sun (long term, a second sun would be terrible, but a supernova does not last that long, so it might be tolerable). When Betelgeuse goes supernova, this distance would be roughly 1 light year (but keep in mind that this is astrophysics and the error bars are usually assigned to the order of magnitude). I suspect that there are no stars within this distance, but my astronomy knowledge is not sufficient to verify that.

 

[Timsup2nothin]

Not to be a nitpick, but technically, "now" means a 1400 year long interval when talking about an even that occurs at a distance of 700 light years. The past begins when something moving at light speed could have hit us.

Doesn't such a humanocentric view strike you as somewhat...egotistical?

 

[red_elk]

Not to be a nitpick, but technically, "now" means a 1400 year long interval when talking about an even that occurs at a distance of 700 light years. The past begins when something moving at light speed could have hit us.

I believe we can define the "now at Betelgeuze" moment, it's just going to be different for each observer and depend on the direction and speed of his movement relative to Betelgeuze. The Earth's orbital movement should shift it back and forth depending on season.

 

[uppi]

Doesn't such a humanocentric view strike you as somewhat...egotistical?

No. From the point of view from Betelgeuse, "now" on Earth is equally long. There is nothing special about using the solar system as a reference system, but if you want to compare astronomical events to events in your life, it tends to be a very useful one.

I believe we can define the "now at Betelgeuze" moment, it's just going to be unstable and depend on the direction of our movement relative to Betelgeuze.
It should be fluctuating back and forth every year, since the Earth's orbital speed is 1/10000 of the speed of light and the Sun's relative speed is roughly constant.

If the distance between two events is longer than the time (multiplied by the speed of time) between two events (regardless the reference system), you can always find a reference system in which the events happen at the same time. So past, present and future are defined in terms of causality: an event can be affected by past events, it can affect future events, and cannot have any causal relationship to present events.

 

[hobbsyoyo]

No. From the point of view from Betelgeuse, "now" on Earth is equally long. There is nothing special about using the solar system as a reference system, but if you want to compare astronomical events to events in your life, it tends to be a very useful one.



If the distance between two events is longer than the time (multiplied by the speed of time) between two events (regardless the reference system), you can always find a reference system in which the events happen at the same time. So past, present and future are defined in terms of causality: an event can be affected by past events, it can affect future events, and cannot have any causal relationship to present events.

I don't follow most of this post.

 

[red_elk]

If the distance between two events is longer than the time (multiplied by the speed of time) between two events (regardless the reference system), you can always find a reference system in which the events happen at the same time. So past, present and future are defined in terms of causality: an event can be affected by past events, it can affect future events, and cannot have any causal relationship to present events.

That's right, I mean for reference systems we commonly use on Earth, the interval of "now" should be much narrower than 1400 years (few days perhaps?). We can only travel at slow speeds.