THE SOUTHWORTH PLANETARIUM
207-780-4249 www.usm.maine.edu/planet
70 Falmouth Street Portland, Maine 04103
43.6667° N 70.2667° W
Altitude: 10 feet below sea level
Founded January 1970
Julian Date: 2458851.16
Julian Date: 2458851.16
2019-2020: LXXX
"Do you think they'll still have the Super Bowl now, or is it not worth it?"
THE DAILY ASTRONOMER
Monday, January 6, 2020
Betelgeuse Going Bust?!
Is Betelgeuse, the supermassive red supergiant star marking Orion's eastern shoulder, about to go supernova? Meaning, is it about to explode and produce a spectacle so gorgeous and gob stopping that all of humanity en masse will be reduced to gasps and stunned with wonderment? Not only has such a celestial sight not been seen for centuries, it would be the closest and brightest supernova to ever inflame our firmament in recorded history and perhaps for thousands of years prior! Are we...WE about to behold something so marvelous that no subsequent cosmic occurrence will ever upstage it? Is this the time for all of us to look skyward and proclai....
Ok, look, I'm going to stop writing for a moment and just talk to you. I remember in the journalism class I flunked out of, we were taught the trick of the hook, which is not nearly as prurient an activity as it sounds. The concept was simple: you ensnare the reader with a hook or a tease, something that will induce the person to continue reading even if the content of the article that follows doesn't actually support the initial assertion or even contradicts it altogether. The hope is that the reader will read through all the copy (including the craftily concealed advertisements) and be so befuddled by the column's actual content that he or she will forget they were duped in the first place.
The aim is to make you think that Betelgeuse is about to do the big firework so soon you feel compelled to run outside and watch as the shock wave shatters all the car windows. Then, of course, as you keep reading, you will learn -much to your distress- that most astronomers don't really believe that Betelgeuse is about to go supernova. Instead, they have observed that the star is noticeably dimmer than it has been for many years. While this variability is not unusual as Betelgeuse is a variable star, the brightness diminishment is significant enough that some astronomers wonder if, perhaps, it is a precursor to Betelgeuse's demise in a supernova explosion.
Fortunately for you, the DA abides by a strict code of conduct and would never actually stoop to such underhanded tactics to ensure that the readers continue to the end. It is a point of pride with us that readers hardly ever make it to the end of these articles. Now, we should explain that Betelgeuse will eventually explode as a Type II Supernova. Such a supernova causes a star to literally explode from the inside out.
To explain why this explosion happens, we should first point out that
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like all stars, Betelgeuse is converting lighter elements in its core into heavier elements through a thermonuclear fusion process. For instance, the Sun is fusing hydrogen into helium presently. In about five billion years, it will deplete its core hydrogen reserves and begin (after a flash) helium fusion processes that will produce carbon. However, the Sun isn't massive enough to produce temperatures necessary for more advanced fusion reactions. Betelgeuse, however, is sufficiently massive to produce fusion reactions up to iron. Unfortunately, iron fusion is endothermic: the energy the star invests to sustain these fusion reactions is greater than the energy the reactions would impart back into the star. The balance between the energy pressure pushing outward and the gravitational contraction pushing inward is so violently disrupted that the star collapses in on itself and explodes. The resultant energy release ignites the supernova explosion. In the process, it also creates all the elements heavier than iron.
Astronomers know that Betelgeuse's age is about 8.5 million years: a ripe old age for such a star as the highly massive stars have the shortest life spans. Its age is clearly evident by its enormous size: 160 million Suns could fit neatly inside it. Such bloating is indicative of the star's senescence. Consequently, its death by supernova is inevitable, but not necessarily imminent. It could explode "soon," which in astronomical parlance means within the next 100,000 - 200,000 years. As clever as astrophysicists tend to be, they don't know enough about stellar life cycles to know precisely when a supernova will occur. It is akin to geologists who know that California is due for a truly latte-spilling temblor . but can't pinpoint a precise time the big shake will happen.
Now, it is possible that we could actually see Betelgeuse explode as a supernova. If that does happen, by heavens, the sight will harrow up our souls, freeze our young blood and make our two eyes like stars start from their spheres. (After teaching us about hooking, the journalism professor said, 'if you lack ability, just steal from Shakespeare') Betelgeuse will be brighter than any other night sky sight, including the moon! It will cast a distinct shadow on us at night and be visible during the day. After a few weeks, it will fade into invisibility, leaving a complex web of filaments in its wake: super heated. metal-rich filaments expanding at a furious rate to chemically enrich its local environment.
What might be equally as impressive is seeing Orion after Betelgeuse is gone: the mighty Hunter sans eastern shoulder: the rectangular outline suddenly rendered triangular. Moreover -and this is the bit that will make each particular hair to stand on end like quills upon the fretful porpentine- if we do see Betelgeuse erupt as a supernova, we'll actually be watching an eruption that happened about 620 years ago, as Betelgeuse is 620 light years away. If any of us sees Betelgeuse perish, we will realize that it has been dead for centuries! All this time we've been admiring Betelgeuse, watching it looming high over our winter skies or seeing it descend into the western May twilight, we haven't been seeing Betelgeuse at all....only its phantom: the last light traces of a star that hasn't existed for more than six centuries.
While we might never see that explosion, it is possible that this sudden brightness diminishment could be a warning that Betegeuse is about to die...or, more correctly, actually died in the early 15th century. We don't know, yet, but what better way to keep people looking up at the gigantic hunter now adoring our evening sky.
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And now for the following exchange with a subscriber
called "The Questioning Educator."
QE: I have a question for you....is a new decade really beginning? Was there a year 0? Just curious. I do concede that the 20s are starting. Just something to ponder.
DA: Yes, you are correct.
The 21st century started on Jan 1, 2001, not Jan 1, 2000, as is popularly believed. For this reason, the century's first decade started on January 1, 2001 and ended on December 31, 2010. The century's second decade started on January 1, 2011 and will end on December 31, 2020.
Consequently, we are still in the last part of the century's second decade.
On the other hand, because the year ends in '20,' we can consider the 20's to be starting now.
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