Thursday Throughput: Exploding Betelgeuse Edition
[ThTh1] Betelgeuse is a bright red supergiant star in the shoulder of Orion. It is massive: a thousand times the radius of the Sun, twelve times the mass and a hundred thousand times as bright. It is in its death throes and will go supernova within the next hundred thousand years or so.
Recently, it suddenly and unexpectedly dimmed, dropping in brightness by a factor of two over the last ten weeks or so. This seems to be unprecedented and is raising speculation about whether or not it is about to explode.
The answer, for this week’s Ask an Astronomer is: probably not.
We actually don’t know a lot about how massive stars go supernova and certainly not enough to make predictions to any accuracy beyond a few hundred thousand years. Part of this is a lack of theoretical and empirical knowledge: supernovae are rare so we don’t get to study their final stages very often. But part of it may be intrinsic. The last stages of a massive star’s death take place over a short span of time — decades, years, eventually days. There simply may not be enough time for that information to propagate to the surface in ways we can observe.
So it’s certainly possible that Betelgeuse is on its way to a supernova and this is the precursor. But it’s extremely unlikely. Stars at this stage of their life vary their brightness a lot and Betelgeuse specifically has multiple variabilities of varying strength and periods which have been documented over a thousand years. So while what it’s doing is interesting, it’s not unprecedented.
What I tell my students is that Betelgeuse will explode in the next thousand centuries. That could be a thousand centuries from now or it could be tomorrow. The dimming is interesting. But it doesn’t change the overall math at all. Betelgeuse could explode tomorrow. Or it could explode a thousand centuries from now.
[ThTh2] A beautiful visualization of planetary orbits.
[ThTh3] And another visualization of just how deep the sea is.
[ThTh4] New research is showing us exactly how the Chicxulub meteor killed the dinosaurs.
[ThTh5] How can we stop global warming? A massive investment in R&D.
[ThTh6] And we could also look at why some trees are way better than others at sequestering carbon.
[ThTh7] I rarely endorse alternative medicine, but this guy seems to be onto something.
[ThTh8] Cats do, in fact, pass the mirror test.
[ThTh9] I hope you all are having an excellent solstice season. In about a month, we’ll be the closest the Earth gets to the Sun. Then we’ll start drifting out while the Earth moves and the orientation of the tilt changes. Put in layman’s terms: summer is coming.
I agree we don’t spend enough on R&D, but I don’t trust government to not piss such money away on obvious crap (solar roadways!) or graft/giveaways.
We’d need some kind of governing body that is politically disconnected. Congress just hands them $X B a year and they figure out where to target it.Report
Agreed absolutely. This is why the NSF and (to some degree) NASA and DOE are successful. Congress gives them a budget and scientists decide what it goes it. It’s not perfect but it’s way better than deciding contracts based on campaign donations.Report
I’m not sure how well that would apply to NASA. To make it politically viable, NASA spending was spread throughout key states and districts, and big contracts are divvied up between both the major centers and the various big contractors, who spread the funding to subcontractors. Military spending shows the same pattern, with all the important Congressional districts getting components of whatever super-fighter is being built.
Funding for astronomy just generally isn’t big enough to be that important to campaigns except for the occasional big-ticket item like the James Webb space telescope.
The pork must flow.Report
I’ve wondered about SpaceX and the spreading-the-production-around model. As of a few years ago, they were bringing more and more parts production in-house. Musk said it was because of price gauging by the parts providers, and also hinted at the costs of dealing with the steady trickle of outside companies that get caught faking testing and QC reports.Report
That’s exactly the issue. One of the first things Musk did when he became interested in launching a probe to Mars is ask why rockets were so ridiculously expensive. It seems much of the problem is the standard aerospace (DoD) contracting model, which is designed to appease as many powers-that-be as possible instead of producing low-cost high-end products.
There were certainly other elements that drive up costs, such as low-volume production of sophisticated rocket turbo pumps. The machine tooling required to produce them is staggeringly expensive, yet the number made are very small, so obviously the cost per unit is extremely high. Musk went with a commercial pump manufacturer, Barber-Nichols, whose volumes were high and who’d already done some work on rocket turbopumps as part of some NASA cost-savings experiments.
Of course another element beyond the old Henry Ford philosophy of doing everything under one roof is Musk’s focus on simplicity and cost.
I’m not sure how much astronomy could gain by trying to go for high-volume standardized production of fairly large telescopes. As it is, almost all the projects are one-offs, so there’s no basis for comparison once the scopes are much bigger than retail Meades and Celestrons.Report
What do you think of this (by another Siegel!) which says it could have exploded already?
https://www.google.com/amp/s/www.forbes.com/sites/startswithabang/2017/03/22/what-will-happen-when-betelgeuse-explodes/amp/Report
It certainly could have. We don’t worry too much about lookback time locally but with something as sudden as a nova, it does matter. Probably about a 1% chance it has already exploded and the light is on its away to us. First indication will probably be a blast of neutrinos from the collapsing core, which will preceed the light.Report
RIP Planet of the Apes.Report
I was intrigued by a story about cotton candy planets.
NASA.gov news story
The planets are the size of Jupiter but their mass is not much different from Earth’s. They are thought to be very young, and so haven’t had much of their hydrogen-helium atmospheres stripped away yet.
I’ll have to think about how gas laws are going to scale where the upper reaches of the atmosphere are feeling only a weak pull from the planet’s core.Report