Ode To Telescopes
[My story in the Outlook section. I'll post annotations, amendations, retractions, denials, etc., later today after I sort through the email, the snail mail, the hate mail, the messages arriving by pigeon and the various slanders hurled from unkempt strangers standing on milk crates.]
I dropped by NASA headquarters last Monday to hear about the relatively nearby [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] 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.
This new look at our friendly neighborhood Death Star follows the observation, last September, of a much more distant supernova, which scientists have given the lovely name of SN 2006gy [in the galaxy NGC 1260 for those of you wanting to put a little red pin on your cosmic map]. This was a gargantuan star much like Eta Carinae. The orthodoxy had been that "Eta Car" would have to go through a gradual process of shedding its "hydrogen envelope" before it would explode. But SN 2006gy didn't bother with that. And while most stars that explode leave behind a solid core of material, this star annihilated itself. Nothing left but fireworks.
[In last Tuesday's Washington Post, my esteemed colleague Marc Kaufman wrote, "If that nearer star, named Eta Carinae, blows up like the one just discovered, they said, it could possibly spew dangerous radiation in Earth's direction. More likely, however, it would erupt into the most luminous star in our sky ..." There was a lot riding on the phrase "more likely." The nervous reader no doubt studied the placement of the story in the newspaper to try to glean some information about how worried we should all be. It was front page. But it was just a narrow, one-column story. But above the fold! And clearly placed in the "lead" position on the right side of the page. And yet dominating the page was the big photo of the president in white tie next to the Queen wearing a tiara. So you got these people pretending it's still the 19th Century. Reassuring? Or another harbinger of doom? There was a lot there to ponder.]
The bulletins from space arrive almost daily. More than 200 "extrasolar" planets, far from our own solar system, have been found over the past dozen years. Most are "hot Jupiters" -- gas giants in tight, scorching orbits. But just last month, astronomers said they'd found, mixed with the light of a nearby star, the signature of a planet that might be rocky like the Earth and orbiting at a distance at which liquid water and life could be possible. And last week, astronomers at Harvard said they'd made a rough map of another extrasolar planet that they believe has a big red spot and is buffeted by powerful, hot winds.
But behind all this stellar news is another headline: We are in the golden age of telescopes. We know what we know about SN 2006gy and Eta Carinae and all the rest because computer-aided telescopes, both on the ground and in space, have checked them out in multiple wavelengths, from the visible to the X-ray. And we're seeing a more interesting, chaotic and preposterously vast universe than anything Galileo could have imagined.
Space-based astronomy is a part of our space program that really works. Space science has been a great investment at a time when we've found so many ridiculous things upon which to waste billions of taxpayer dollars. But the NASA science budget, currently $5.5 billion, has leveled off after years of growth, and some major telescope projects have already been put on the far back burner. [Like this one.] The budget is likely to remain tight as the agency follows President Bush's "Vision for Space Exploration": to send astronauts back to the moon. It's a goal that might make some long-term sense if we're going to become citizens of the entire solar system, though it remains to be seen whether the public really wants to pay for astronauts to land on the moon 'round about the 50th anniversary of the first time they did so.
In coming years, policymakers will need to remember that telescopes give a big bang for the buck. Each new instrument changes our view of the universe. Go back to Galileo: His great revelation was not merely that Jupiter had some little satellites orbiting it, or that Venus had phases like those of the moon, or that the moon had features that looked like mountains, but that all of these things in the sky were worlds, that they were in the same general category of object as the Earth. Science has steadily removed us from our privileged position in the cosmic scheme of things. Are we really alone? Astronomy may give us the answer.
From my email inbox:
From R. Freeman: "I'm a boomer, and grew up 'knowing' I would be a fighter pilot then an astronaut. Bad eyes sank that dream, but I hope I'm still around when a human being steps onto the sands of Mars. Hope it's an American, too. But, if we keep squandering wealth on wars instead of space exploration, it might not be. And if we keep putting corporate profits ahead of innovation, creativity, and efficiency, some other country is going to get there first."
R. Stolzberg writes: "Aren't you unduly optimistic about the safety we gain from eta car. being 7500 light years away? if it blew up 7499 years ago, we wouldn't know it and its radiation would hit us in about a year. or am i missing something?"
A: You are correct in your math, but 7,500 light years is a very long way away. If Eta Carinae were 4 light years away I might be more worried. But since the energy of the explosion is radiating in all directions, the amount of energy that would be intercepted by our distant, pale blue dot is very slight. That's my story and I'm sticking to it.
P. Mathieu writes: "When we detect an object that's over twelve billions light-years away, we are seeing the object as it was soon after Big Bang at a time when we were all flying out from the center, thus rather near each other; why has it taken over twelve billion years for the light to reach us from what was then near us?"
A: This one is tricky and I can't quite figure out how to answer it. We should direct it to the astrophysicist who will join me online Wednesday at 1 p.m.. The short answer, I think, is that the galaxies are not expanding into some pre-existing space. Rather, space itself is expanding. The "big bang" is not a singular event but is the start of this prolonged expansion process that might at one point have involved a rapid "inflationary" epoch or two that stretched the dimensions of the universe from very small to very large in a fraction of a second. Hold on while I root around in my files for something on cosmic inflation....Stand by....[muzak version of The Blue Danube plays in background]... Here ya go!
bc: '...the weak spots in those stellar magnetic fields along the axis of rotation act like a magnetic gunbarrels at both
ends for hard radiation that the stellar body may be spewing out (as a side note, black holes emit signature X-ray "burps" along these axes as matter is being drawn into the event horizon). All of that radiation is channeled from across the stellar body out through a relatively small hole, in a fearfully condensed and energetic fashion. I think of it as a big particle beam ray gun.
'So, it occurred to me that one way to assess the danger posed by nearby stars that fit a profile of going nova (super-, hyper-, bossa-, whatever), would be to determine those star's axis of rotation, and whether it intersects Sol's orbit around the center of the Milky Way.
'While it would be logical to infer that the most stars in the Milky Way axes of rotation would line up more or less with the Milky Way's roataion (and the main galactic disc), that inference would be incorrect. The Sun (and the plane of the Solar ecliptic), for example, is flipped over 60 degrees to the main plane of the Milky May (the northern axis aligned more or less at the North Star), so it'd take some research and observation to figure out how many threats there may be from that.'
[Here's the story, cited in the boodle, about nasty comments online.]
The comments to this entry are closed.