Betelgeuse To Blow Up Soon — Or Not

rubycodez writes "A wave of 2012-related hoopla has hit the internet about the star that makes the 'right shoulder' of Orion the hunter: Betelgeuse. Astronomer Phil Plait once again puts rumors to rest. The star will indeed explode as a type II supernova, and when it does it will be brighter than Venus when viewed from Earth, though not as bright as the full moon. It will be visible in the night sky for weeks, and could be visible in the day sky for a short time. But that event could happen today or 100,000 years from now, or as much as a million years from now. Since Betelgeuse is over 600 light-years away, its violent death will not harm Earth in any way, but will definitely provide a huge bonanza of scientific information about supernovae. As geeks, we can only hope the core of Betelgeuse undergoes catastrophic failure in our lifetime."

Comments

Soon?

[RabbitWho]

What they're saying is it might have blown up around 600 years ago... or not

Re:Soon?

[Anonymous Coward]

To you and the other 17 people who have already stated this and who will state this, we know. But we don't mention it, because it's irrelevant. Some of those who state it are just pointing out an interesting fact, which is fine, but to those who are stating it like it changes the story itself, or the importance of the story, or the facts of the story--shut up.

Re:Soon?

[Kjella]

Long story short, our full motion is measured relative to the background radiation. The earth rotates around itself, around the sun, the sun rotates around the milky way and the milky way is moving itself. In total we move about 0.2% of lightspeed, and time dilation is relative to the fraction of c squared so time goes about 0.0004% faster than at rest. Imagine you stuck your finger in still water, the circle it'd make would continue to grow and the wave would go on forever but get thinner and thinner. Same thing with the universe, the distance to the edge keeps increasing but the earth and moon isn't being pulled apart by space "stretching". All this is really on a much grander scale though, in terms of a planet 600 light years ago it's like asking if you can find your way down to the corner store without taking into account that earth is round.

The difficulty is in trying to get an accurate angle measurement, even taking pictures from both sides of the earth we only get a ~13000 km wide angle which is small when you're trying to see an object ~5000000000000000 km away. For Betelgeuse wikipedia lists the distance as 643 ± 146 ly so the uncertainty is almost 300 ly. If we could travel even a tiny bit in any direction that'd matter on a stellar scale and photograph the sky we'd have much, much, much better estimates on the distances. That said, we can still do a lot more from earth or near earth than we have so far and there's plans for far better telescopes than today, first up probably the James Webb Space Telescope in 2014 or 2015. Also ground based telescopes keep getting larger and better, even though the atmosphere limits them somewhat.

Re:Soon?

[Ruie]

Stellar parallax is usually measured using positions of the earth at different points of the orbit around the sun, which provides a much longer measurement base.

Re:Soon?

[Ruie]

All good questions and guesses ! You should go get a Physics Ph.D., it is much fun !

After the Big Bang occurred the matter was very very hot. So it looked basically like fire. But since entire universe was "on fire" and light has a finite propagation speed we can still see light just reaching us now from very far away places in the universe - Cosmic Microwave Background.

It has many interesting properties. First, as you point out you can measure our speed relative to it. Secondly, it has a very long wavelength which is due to expansion of the universe - the places farther away are moving away from us.

The expansion of the universe is actually very very small even on the scales of a solar system or galaxy and starts to matter on the intergalactic scales. It is characterized by Hubble constant= 70 (km/s)/Mpc - for each million parsecs the speed goes up by 70 km/s. For comparison, Earth's orbital speed is 30 km/s and the size of the entire Milky Way (our galaxy) is only 30 thousand parsecs.

Yes, there is a time dilation effect.

Btw, speaking of time dilation effect, the scientists at NIST has recently built an atomic clock based on a single Aluminum atom that is so accurate that they can see time dilation from Earth gravitational field. They measured the rate of their clock, than raised the setup and measured a faster rate - clocks slow down in stronger gravitational field and Earth field decreases by a small amount as you get further away from Earth.

Betelgeuse Betelgeuse Betelgeuse

[tverbeek]

Just say its name three times and it'll all be under control.

Re:I can see it now

[Anonymous Coward]

During a type II supernova most of the iron stays in the core and isn't cast off.

Insurance

[chill]

The question is, can I make money selling Betelgeuse supernova insurance to the general public?

Party?

[gregor-e]

Driving home one evening, someone said we should hold a party for the death of Betelgeuse, and invite Michael Keaton. My girlfriend responded "Why? Because he's a dying star too?"

Re:Already happened?

[DJLuc1d]

There is a mistake in thinking like this. You assume an absolute version of time. Relativity shows us that this is not the case. There is no universal time clock, and since nothing can be transmitted faster than light, not even information (barring crazy stuff like quantum entanglement) - it only matters when we observe it. Like the uncertainty principle, all common thinking tells is is that the atom must have a definite position and velocity - but it doesn't because we can't measure it. Same applies here, we can't measure things until the information reaches us, so that is when it happens.

Re:What about Ford Perfect?

[GreatDrok]

I don't know about Ford Perfect, but Ford Prefect may well have an issue with this.

Re:Already happened?

[dsanfte]

Calm down, he's obviously talking about his own inertial reference frame. And within his frame, he's correct.

Re:Already happened?

[Shimmer]

We can't measure things until the information reaches us, so that is when it happens.

I think you are misunderstanding relativity, or perhaps just miscommunicating it.

Example: Some cosmic microwave background radiation from the early universe is just reaching Earth today. That doesn't mean that the universe is young "now".

My understanding of relativity is that you can still use distance = speed * time to figure out when an event occurred in your reference frame. You just have to give up the notion that everyone else will agree with you.

Re:Let's hope that..

[mrsquid0]

It is extremely unlikely that Betelgeuse will produce a gamma-ray burst. The current thinking is that supernovae only produce gamma-ray bursts in stars that have been stripped of their hydrogen envelopes. Betelgeuse still has most of its hydrogen, and there is not enough time to lose it before the supernova is likely to happen. Even if Betelgeuse does produce a gamma-ray burst the bursts occur along the rotation axis of the star, and Betelgeuse's rotation axis is not pointed towards us. Fortunately, we do not have to worry about a gamma-ray burst from Betelgeuse, because it is close enough that such a burst would be rather nasty for us.