I remember a time when it seemed like I was the only person in the world who knew that stars we could see in the night sky might one day go foom, letting us read at night or, possibly, destroying the habitability of our planet. Of course, I couldn’t have been alone in knowing this, since I found out about it by reading books by other people, but in the dark times of Web 0.1, before writers and scientists were people who listened to music and got in spats with one another, it was easy to feel alone while exploring the heavens.
And now, look, everybody who reads the Washington Post knows about Eta Carinae, thanks to Joel Achenbach:
I dropped by NASA headquarters last Monday to hear about the relatively nearby and extremely massive star that might explode at any moment. Remember the name: Eta Carinae. Sounds like an Italian opera singer, or maybe a snazzy little sports car. It’s a monster of a star — something like 120 times the mass of the sun, and roiling, heaving, spewing out gobs of star stuff in what may be the prelude to a cataclysmic bang, a supernova unlike any seen before.
If it blows, you might be able to read a book by its radiance at night — unless it fires a narrow beam of gamma rays right at us, in which case all bets are off. One astrophysicist on hand said, “It would probably destroy all the ozone in the atmosphere.” Similar to what we tried to do ourselves, before we banned those nasty chlorofluorocarbons. Eta Carinae would be like a giant can of 1950s hairspray. Not a pleasant picture.
“Relatively nearby” is, of course, a vague layman-speak of what the astronomers can say much better. Achenbach adds, parenthetically,
now there’s a squishy term if I ever saw one: the star is 7,500 light years away, which, as I note at the end of the piece, is a long hike. That’s close to a tenth of the way across the entire galaxy. A light-year is about 6 trillion miles. So to express the distance in miles to Eta Carinae you have to resort to “quadrillions,” which we can all agree is a silly word.
Not as silly as — tee hee! — sextillions. And it gets worse:
Did you know that a myriad is officially 104? Or that a lakh is 105 and a crore is 107? (I guess they’re not joking when they say the Lakh Ness Monster is really big.) I’m not making any of this up — it comes straight from p. 16 of Conway and Guy’s Book of Numbers. They even give some examples of Japanese names for big and little powers of ten (many of which are apparently of Indian origin). They call 1056 kougasha, “sands of the Ganges,” while 1080 is fukashigi — “don’t even think about it” — and 1088, muryoutaissu, translates as “large amount of nothing.”
Wow, I clearly need that book of numbers… it had me laughing aloud (: The Japanese have a great sense of humor.
So, the end of all life on the planet notwithstanding, you’ve got to admit: it would be amazing if the star had aim like that!
I’m skeptical that Eta Carinae would pose a threat to life if it went boom. It’s certainly not anything like what is thought to be the precursors to gamma ray bursts, as is implied by the quoted text. Betelgeuse certainly provides more to be concerned about.
I tried to look up some actual figures, but my search engine-fu must have been weak. Apparently, the worry (and it is an extremely long shot) is that SN Eta Carinae would be comparable to SN 2006gy, with an apparent magnitude of around -7.5 (about thirteen times brighter than Venus at its maximum, I think) and a slim chance of a gamma-ray flash heading our way.
According to Dar and DeRujula 2002, the rotational axis of Eta Carinae is between 10 and 57 degrees off our line of sight, so any gamma ray burst from that star will not be coming our way.
Good news!
Another paper on the threat posed by Eta Carinae: arXiv:0705.4274v1 [astro-ph]. There are probably lots more.
Tristram Brelstaff:
Many thanks for the pointer. I might write up something about that soon, now that I’m collecting references.