Is Betelgeuse About To Explode?

A ripple of excitement is passing through the community of astronomers, both amateur and professional, at reports that Betelgeuse has dimmed significantly over recent days. Is it revving up for a spectacular explosion? Maybe!

Image result for Is Betelgeuse About To Explode?

Those who study the star most closely are hosing down the idea the world is about to experience perhaps the greatest event in the history of astronomy, but that doesn’t mean there isn’t something interesting going on.

To understand the fuss it is necessary to know that Betelgeuse, the deep red star in Orion’s shoulder is a red supergiant with a mass large enough that it will inevitably become a supernova one day. Moreover, given its development, that day will be soon, by astronomical standards.

When this occurs, it will be a truly awe-inspiring sight. Betelgeuse is conveniently placed, far enough away there will be no danger to Earth, but close enough that its brightness will be breathtaking, possibly outshining the full Moon.

While there are several nearby stars that will eventually become supernovae, Betelgeuse probably heads the queue. There is general agreement its maximum life expectancy is less than a million years, and one study estimates its remaining life at 100,000. An explosion in our lifetimes is not likely, but more credible than for fellow supergiants like Antares or Spica.

The color-magnitude diagram of notable stars. The brightest red supergiant, Betelgeuse, is shown at the upper right.

The color-magnitude diagram of notable stars. The brightest red supergiant, Betelgeuse, is shown at… [+] EUROPEAN SOUTHERN OBSERVATORY

Consequently, the report of a sudden dip in brightness, referred to as a “fainting”, hasn’t been received quite the way it would have with any other star. Nevertheless, two explanations have been offered, each more likely than the possibility this is a prelude to stellar Armageddon.

The first point astronomers have noted is that Betelgeuse is a variable star, whose brightness is constantly changing. Although recent measurements have it fainter than anything previously recorded, we know it is operating on multiple cycles. When the minimums of each cycle come together, the star will look particularly faint, but will brighten soon after.

Alternatively, with a stellar wind ordinarily a million times that of the Sun, Betelgeuse could have ejected more dust than usual, obscuring it enough to cause the dimming. Either way, establishing the explanation should be fun, but not that much fun.

Meanwhile, the nearby supernova drought continues. A galaxy the size of the Milky Way would normally have around one supernova every 100 years. Yet not has been seen since the invention of the telescope, the last occurring in 1604. The only supernova visible to the naked eye since then occurred 32 years ago in the Large Magellanic Cloud, a hundred times more distant than Betelgeuse, and astronomers are still writing papers on what they saw.

Oh well, at least we get to marvel a little longer at a star so bloated Jupiter’s whole orbit would fit inside. And there is always Eta Carinae.   Source IFLSccience

What Will Happen When Betelgeuse Explodes?

Image result for Is Betelgeuse About To Explode?

Every star will someday run out of fuel in its core, bringing an end to its run as natural source of nuclear fusion in the Universe. While stars like our Sun will fuse hydrogen into helium and then — swelling into a red giant — helium into carbon, there are other, more massive stars which can achieve hot enough temperatures to further fuse carbon into even heavier elements. Under those intense conditions, the star will swell into a red supergiant, destined for an eventual supernova after around 100,000 years or so. And the brightest red supergiant in our entire night sky? That’s Betelgeuse, which — as Jillian Scudder explained fantastically in 2015 — could go supernova at any time.

Honestly, at its distance of 640 light years from us, it could have gone supernova at any time from the 14th century onwards, and we still wouldn’t know. Betelgeuse is one of the ten brightest stars in the sky in visible light, but only 13% of its energy output is detectable to human eyes. If we could see the entire electromagnetic spectrum — including into the infrared — Betelgeuse would, from our perspective, outshine every other star in the Universe except our Sun.

In addition, it’s constantly losing mass, as the intense fusion reactions begin to expel the outermost, tenuously-held layers. Direct radio observations can actually detect this blown-off matter and have found that it extends to beyond the equivalent of Neptune’s orbit.

But when we study the night sky, we’re studying the past. We know that Betelgeuse, with an uncertain mass between about 12 and 20 times that of our Sun, was never destined to live very long: maybe around 10 million years only. The more massive a star is, the faster it burns through its fuel, and Betelgeuse is burning so very, very brightly: at around 100,000 times the luminosity of our Sun. It’s currently in the final stages of its life — as a red supergiant — meaning that when the innermost core begins fusing silicon and sulfur into iron, nickel and cobalt, the star itself will only have minutes left.

At those final moments, the core will be incredibly hot, yet iron, nickel and cobalt will be unable to fuse into anything heavier. It’s energetically unfavorable to do so, and so no new radiation will be produced in the innermost regions. Yet gravitation is still at play, trying to pull the star’s core in on itself. Without nuclear fusion to hold it up, the core has no other options, and begins to implode. The contraction causes it to heat up, become denser, and achieve pressures like it’s never seen before. And once a critical junction has passed, it happens: the atomic nuclei in the star’s core begin a runaway fusion reaction all at once.

This is what creates a Type II supernova: the core-collapse of an ultra-massive star. After a brief, initial flash, Betelgeuse will brighten tremendously over a period of weeks, rising to a maximum brightness that, intrinsically, will be billions of times as bright as the Sun. It will remain at maximum brightness for months, as radioactive cobalt and expanding gases cause a continuous bright emission of light.

Supernovae have occurred in our Milky Way in the past: in 1604, 1572, 1054 and 1006, among others, with a number of them being so bright that they were visible during the day. But none of them were as close at Betelgeuse.

At only 600-or-so light years distant, Betelgeuse will be far closer than any supernova ever recorded by humanity. It’s fortunately still far away enough that it poses no danger to us. Our planet’s magnetic field will easily deflect any energetic particles that happen to come our way, and it’s distant enough that the high-energy radiation reaching us will be so low-density that it will have less of an impact on you than the banana you had at breakfast. But oh, will it ever appear bright.

Not only will Betelgeuse be visible during the day, but it will rival the Moon for the second-brightest object in the sky. Some models “only” have Betelgeuse getting as bright as a thick crescent moon, while others will see it rival the entire full moon. It will conceivably be the brightest object in the night sky for more than a year until it finally fades away to a dimmer state.

Unfortunately, the key question of “when” is not one we have an answer to; thousands of other stars in the Milky Way may go supernova before Betelgeuse does. Until we develop an ultra-powerful neutrino telescope to measure the energy spectrum of neutrinos being generated by (and hence, which elements are being fused inside) a star like Betelgeuse, hundreds of light years away, we won’t know how close it is to going supernova. It could have exploded already, with the light from the cataclysm already on its way towards us… or it could remain no different than it appears today for another hundred thousand years




Read previous post:
Experts Creating New Astronomy Signs For The Deaf

Most UK deaf people use British Sign Language, which has...

Unopened Moon Dirt To Be Unwrapped Soon.

NASA celebrated the 50th anniversary of the historic Apollo 11...

New Addition: Kids Space/Sun Packs

NEW FOR CHRISTMAS 2019            ...