This is the nearby spiral galaxy NGC 1345 as seen by Hubble. Lovely, isn’t it? You wouldn’t even think it’s a spiral at first; the arms are so faint compared to the sprawling core and inner regions. But it so happens the galaxy is close to our own, making fainter parts easier to observe
Now there you go. Did you see that? What I said? "The nearby spiral…". "The galaxy is close to our own…". But it isn’t.
Look. Let your eyes move to the top of the galaxy, just to the right of center. See that bright star? You can tell it’s a star because it has those spikes going through it, an artifact of how point sources are seen by some of the Hubble cameras.
Given how bright it is, that star is almost certainly in our own galaxy, and not some luminous giant in NGC 1345; it’s just coincidentally superposed on the more distant galaxy. That means it’s no more than a few thousand light years away, and given its deep red color, that means it’s most likely a very cool and faint red dwarf, and therefore in all likelihood much closer even than that.
But even if it’s only a thousand light years away, that’s 10 quadrillion kilometers! That distance is impossible to imagine: it’s more than 60 million times farther away than the Sun… and the Sun is hardly close. If you could fly an airplane to the Sun, it would take 20 years. Twenty years! And that star is millions of times farther away.
… and that star is the closest thing in that picture. I said NGC 1345 is nearby, and on a cosmic scale it is; it’s part of a small cluster of galaxies a mere 85 million light years away: 850 quintillion kilometers. That’s 850,000,000,000,000,000,000 kilometers.
"Nearby."Check out the full-size image and read the whole post. It's definitely worth your time.
More mind-bending goodness after the jump.
Brian Greene, author and professor of math and physics at Columbia, is one of my favorite science personalities. His writing helps Bears of Very Little Brain — like me — wrap their heads around some of the universe's most daunting concepts.
I commend to you this op-ed piece from the New York Times, wherein our hero ruminates on dark energy and its possible effects on future civilizations on Earth:
A hundred billion years from now, any galaxy that’s not resident in our neighborhood will have been swept away by swelling space for so long that it will be racing from us at faster than the speed of light. (Although nothing can move through space faster than the speed of light, there’s no limit on how fast space itself can expand.)
Light emitted by such galaxies will therefore fight a losing battle to traverse the rapidly widening gulf that separates us. The light will never reach Earth and so the galaxies will slip permanently beyond our capacity to see, regardless of how powerful our telescopes may become.
Because of this, when future astronomers look to the sky, they will no longer witness the past. The past will have drifted beyond the cliffs of space. Observations will reveal nothing but an endless stretch of inky black stillness.
If astronomers in the far future have records handed down from our era, attesting to an expanding cosmos filled with galaxies, they will face a peculiar choice: Should they believe “primitive” knowledge that speaks of a cosmos very much at odds with what anyone has seen for billions and billions of years? Or should they focus on their own observations and valiantly seek explanations for an island universe containing a small cluster of galaxies floating within an unchanging sea of darkness — a conception of the cosmos that we know definitively to be wrong?
And what if future astronomers have no such records, perhaps because on their planet scientific acumen developed long after the deep night sky faded to black? For them, the notion of an expanding universe teeming with galaxies would be a wholly theoretical construct, bereft of empirical evidence.
We’ve grown accustomed to the idea that with sufficient hard work and dedication, there’s no barrier to how fully we can both grasp reality and confirm our understanding. But by gazing far into space we’ve captured a handful of starkly informative photons, a cosmic telegram billions of years in transit. And the message, echoing across the ages, is clear. Sometimes nature guards her secrets with the unbreakable grip of physical law. Sometimes the true nature of reality beckons from just beyond the horizon.Sobering, but at the same time oddly inspiring.
Lastly, you might have noticed a bit of an astronomy kerfuffle in the news recently. Apparently everyone's star signs got jumbled around because — shock horror! — the little buggers actually move around. Leave it to Seth Shostak, SETI Institute astronomer and world-famous radio host, to put this bout of starry-eyed superstition in its place:
The whole idea that events in the sky at the time of your birth can influence your personality is fundamentally suspect. It lacks any physical basis. Granted, if an asteroid is hurtling to Earth as you're being born, and then vaporizes the hospital a few minutes later, that will affect your personality. But just because Mars is in Aquarius when you pop into the world... well, how could that possibly matter?
Maybe it matters because Mars and the Sun are now pulling on your fetal frame at the same time? You know, the extra tug Mars lends to the Sun if it's in the same direction?
Well, it can't just be the tug of Mars, because Mars is always in the sky. It's just that now it's in a different part of the sky (namely, your zodiacal sign). OK, work it out, and you'll find that the Red Planet's gravitational attraction differs from month to month by less than the pull of the cars in the hospital parking lot. Even Jupiter -- which is really the only planet that counts in this gravitational sweepstakes -- has a variable tug that, from one month to the next, differs by less than that of the office building down the block. Maybe horoscopes should be cast based on city maps.
Frankly, I'll believe in horoscopes the day I can describe my personality to an astrologer, and they tell me what date I was born.