Gamma Ray Bursts - they're neat
March 23, 2008 4:14 PM   Subscribe

How far can the naked eye see? About 7.5 billion light-years. On March 19th, a Gamma Ray Burst was noticed by NASA's Swift satellite and given the name GRB 080319B. It left an optical afterglow estimated at +5 apparent magnitude for 30 seconds, about that of an average star. (Sadly, no one was looking at the area with an optical telescope at that exact time.) Read the original Burst Alert, including the email address of the Burst Advocate, here. posted by ikkyu2 (37 comments total) 7 users marked this as a favorite
 
7.5 billion ly... so, this shit happened *before there was an Earth*. That is mind-boggling all on its own.
posted by synaesthetichaze at 4:19 PM on March 23, 2008 [2 favorites]


I blame Bush.
posted by Balisong at 4:27 PM on March 23, 2008 [3 favorites]


I wonder how many planets it took out and if there was life on them. Amazing. Ours will go boom in about 4.5 billion years. So, you know, get ready, or something.
posted by hojoki at 4:35 PM on March 23, 2008


(Sadly, no one was looking at the area with an optical telescope at that exact time.)

They were all mixing it up at Ironforge.
posted by Smart Dalek at 4:51 PM on March 23, 2008 [2 favorites]


Unfathomable. 1 billion seconds is 32+ years, 7.5 billion seconds is > 240 years. So 7.5 billion seconds is ridiculous to begin with. Light travels 186,000 miles per hour which is about 52 miles a second. So an event 7.5 billion light seconds ago equates to a distance of 7.5 billion light seconds x 52 miles/ second = ~387 billion miles away, 240 years ago. That's light seconds. seconds. seconds, for chrissake. Just think about how long a second is and how long a year is and you don't even need to do the math for how far away/how long ago 7.5 billion light years is. And you could see this with your naked eye? That's ridiculous. Not impossible-ridiculous. Just unfathomable-ridiculous.
posted by Rafaelloello at 5:02 PM on March 23, 2008 [2 favorites]


Have you ever really looked at your hand?
posted by DU at 5:05 PM on March 23, 2008 [4 favorites]


Oh shit. Light travels 186,000 miles per second, not hour. Amend my above post to it's really fucking far away and long ago
posted by Rafaelloello at 5:06 PM on March 23, 2008 [1 favorite]


Bah.

Why is it I can't stretch my arm across the room and my wife is still plainly visible?
posted by tkchrist at 5:10 PM on March 23, 2008


Why is it I can't stretch my arm across the room and my wife is still plainly visible?

On the other hand, I'm on fire right now, so things might work out after all.
posted by Faint of Butt at 5:20 PM on March 23, 2008 [1 favorite]


Rafaelloello, I get 4.4e+22 miles, which is 44,000,000,000,000,000,000,000 miles, or 44 sextillion miles, or 70 sextillion kilometers.

That doesn't mean anything to me. Distance is something I think about traversing; when I think about 7.5 billion light years, I am never going to traverse that or any significant fraction thereof. But I know that when I look across that incomprehensible gulf, I am looking backwards in time. And that's kind of exciting.
posted by ikkyu2 at 5:27 PM on March 23, 2008 [1 favorite]


it's really weird that we can see something now that happened so long ago....so perhaps whatever we emit here on Earth as far as signals will only be capted by another civilization on some planet in billions of years....!
posted by ineedmotivation at 5:58 PM on March 23, 2008


7.5 billion years? At most it was 6012 years ago. Quit trying to ussher in some bullshit date.
posted by maxwelton at 6:04 PM on March 23, 2008 [1 favorite]


Cool post, ikkyu2 . Minor quibble: Asking How far can the naked eye see? is like asking how far can the naked ear hear, or how far can the nose smell? The eye is passive; it doesn't go out there and fetch stuff. If the light is bright enough, the eye will receive it from pretty much any distance, and it's as miraculous as seeing a street light a mile away. This has little to do with the naked eye and everything to do with incomprehensibly big explosions. In a few seconds they give off the equivalent energy of our sun's 4.5 billion year history.
posted by weapons-grade pandemonium at 6:06 PM on March 23, 2008


I blame Bush.
Nononononoooo... 7.5 billion years ago. Blame FDR.
posted by wendell at 6:21 PM on March 23, 2008


After seeing you capitalize every first letter in the phrase "Gamma Ray Burst" I realized that I am going to change my name to "Ray Burst".
posted by subaruwrx at 6:39 PM on March 23, 2008


Hey, if you give off ~1.32x10^54 erg, you'll get capital letters too.
posted by sebastienbailard at 7:37 PM on March 23, 2008


It'll be interesting to see if LIGO was able to detect anything around the time of the burst. Presumably, we should be detecting gravitational waves from these enormous, universe-shattering events. If we don't, then it's back to the Relativity drawing board.
posted by Avenger at 7:55 PM on March 23, 2008


Reminds me of Stapledon's "The Star Maker" for some reason. It could be said that the book shows its age and that it certainly isn't a finely honed prose, but dang if the immense sense of scale he posits isn't fun. Free online txt version.
posted by Burhanistan at 8:03 PM on March 23, 2008


Rafaelloello, I get 4.4e+22 miles, which is 44,000,000,000,000,000,000,000 miles, or 44 sextillion miles, or 70 sextillion kilometers

I had a feeling it was going to be pretty far.
posted by Rafaelloello at 8:11 PM on March 23, 2008


It left an optical afterglow estimated at +5 apparent magnitude for 30 seconds, about that of an average star.

Thought:

If I had seen the optical afterglow, would I have been looking at photons emitted directly from the GRB, or would I be looking at matter between me and the GRB that had been excited or heated by the gamma rays?
posted by ROU_Xenophobe at 8:18 PM on March 23, 2008 [1 favorite]


Rafaelloello, I get 4.4e+22 miles...

Heh. This brings back memories of my first astro class in college. The professor used to slap us down if we said anything like '4.4' and launch into a tirade about significant digits.

Its a tough thing to get your head around. I remember it came up when he was walking us through a method for estimating the size of a galaxy based on some other variable...

Prof: "And so...the size of the galaxy is so-and-so hundred thousand light years [draws a picture of a galaxy with a line across it]"
Student: "But, professor, you've derived the radius of the galaxy, not its diameter!"
Prof: "Thats just a factor of two, meaningless at this scale"
posted by vacapinta at 8:26 PM on March 23, 2008 [1 favorite]


HULK SMASH!
posted by Artw at 9:20 PM on March 23, 2008


up at the chabot space center in oakland they have a pretty trick planetarium. in addition to the star projector thing, they have a computer which drives 3 or 4 projectors, and so they can run a solar system simulator, or indeed a universe simulation.

i've been an astronomy fan my whole life and i've been aware of the scale of the universe for a while. but it never really hit home until i saw the "expanding sphere" demonstration that they do during the planetarium show. a few minutes into his spiel, the guy running the demo pulls the virtual camera out above the solar system, and starts a ray of light from the sun. this is shown as an expanding sphere of light leaving the sun. the demo goes on (in which you fly all the way out to the edge of the known universe) and about 40 minutes later, you end up back in our solar system. the sphere of light has reached... the orbit of jupiter.

all the zipping around the solar system and the universe in the demo happens at impossibly crazy speeds which could never be attained, yet somehow i never really ever realized that such speeds were impossible. you just take it for granted that you can zip around the solar system and such a thing would be possible with the right spaceship.

the speed of light is essentially infinitely fast as far as we're concerned, but light is moving at a snail's pace with respect to the whole universe.

it really was one of those "have you ever really looked at your hand" experiences for me.

as an aside, these "fly around the universe" simulations kind of bug me, since at any interesting distance, what we see now from the earth happened millions and billions of years ago. yet i'm pretty sure that all the objects in the simulation are shown as they look "then" instead of now, since that's all we can see today. so in a sense these simulations are complete bull. i'm always left wondering if these large-scale structures in the universe (like the galactic superclusters, etc.) are thought to have the shape and scale shown in the simulations now, or at some time in the past.
posted by joeblough at 9:20 PM on March 23, 2008 [1 favorite]


Supernova 1987A blew about 160,000 years ago. In 1987, over a period of about 10 seconds, 100 billion of its emitted neutrinos passed through each square centimeter of your body. Source.
posted by neuron at 9:56 PM on March 23, 2008


Cool post, ikkyu2 . Minor quibble: Asking How far can the naked eye see? is like asking how far can the naked ear hear, or how far can the nose smell?

Well, not exactly. I take your point, but walk with me a minute.

The naked ear can't hear any farther than the upper stratosphere - sound doesn't travel in a vacuum. And if the age of the universe is truly 13 billion years (+/- 2.5 byear), the naked eye can't see anything further than 13 billion years away, or whatever that figure is, because then you would be looking into the blackness before the beginning of things. So in that sense, there is a hard limit to how far the naked eye could see, and this GRB is over 50% of the way there.

In fact, the cosmic background radiation, which is the luminosity emitted by that primal event at the start, is not visible to the naked eye at all.
posted by ikkyu2 at 10:33 PM on March 23, 2008 [1 favorite]


This is cooler than Easter.

I am still waiting for the designer drug that will make the visual parts of the brain run very very slowly, enough to get the effect of a long exposure.

A full nigh would go by in a second, but just imagine all one could see in the sky. This is one drug I could become addicted to, enough to spend winters at the poles.
posted by Dr. Curare at 1:35 AM on March 24, 2008


The neatest part to me is that not could you seeing something that happened 7.5 billion years ago, but the photon which would have excited your retina is also 7.5 billion years old.
posted by substrate at 4:50 AM on March 24, 2008


We cannot see something 7.5 billion light years distant. The light came here and we saw that.
posted by dances_with_sneetches at 5:51 AM on March 24, 2008


From my astronomer girlfriend who studies GRBs:

(Sadly, no one was looking at the area with an optical telescope at that exact time.)

There were two that were observing the site of the burst at the time of GRB itself. And many more that responded rapidly.

The peak of the afterglow emission occurred ~30 seconds after the satellite-detected gamma-ray burst itself, and that gave lots of time for robotic GRB-dedicated telescope to respond.

If I had seen the optical afterglow, would I have been looking at photons emitted directly from the GRB, or would I be looking at matter between me and the GRB that had been excited or heated by the gamma rays?

The photons that make up the optical afterglow are thought to be emitted via shocks resulting from the jet interacting with the surrounding environment. These emanate less that 1 parsec from the progenitor star.
posted by hought20 at 8:10 AM on March 24, 2008 [1 favorite]


isnt that kind of like saying we can't see anything? your monitor is 1.6 × 10^-16 light years away from your face, does that mean you can't read it?
posted by joeblough at 8:13 AM on March 24, 2008


sound doesn't travel in a vacuum

Not true, sound out there is just far too low for us to hear. Space isn't a perfect vacuum, and even though the atoms are inches apart they can still propagate waves.
posted by Citizen Premier at 9:36 AM on March 24, 2008


Space isn't a perfect vacuum, and even though the atoms are inches apart they can still propagate waves.

That being said, the speed of sound is still a hell of a lot slower than the speed of light. And I don't think you'll get too many people to agree with your split hair, there, whether or not it is technically "true."

However, this means that all those sf movies with "noise in space" are right after all! Yay!
posted by Guy_Inamonkeysuit at 12:36 PM on March 24, 2008


We cannot see something 7.5 billion light years distant. The light came here and we saw that.
posted by dances_with_sneetches


But that's precisely what happens when you see anything--even the objects on your desk. And you'd admit that you can see them, right? Because of the incredible speed of light, many people don't realize that our eyes just sit there and receive energy, and that takes time. When we see the sun set, it's really not there--it's eight minutes below the horizon. People must think that somehow our vision goes out into the environment and gets stuff and brings it back instantly. It's much easier to understand sound, because it's slower. You don't imagine your ears somehow reaching out and grasping the sound of cars passing or people talking. Sound comes to you. And do you think your nose goes over to a fart and smells it at its source? Not likely. You realize you're smelling something that took place a while ago, and drifted over. Same thing with sight, but with an imperceptible lag, except at cosmic distances. But distance and time are irrelevant for my point, which is that sight is passive, not active.
posted by weapons-grade pandemonium at 1:18 PM on March 24, 2008


Fantastic, hought20. I was going off an early press release.

Now did the relativistic jet interact with all those particles to generate the peak optical afterglow in 30 seconds of our time? Even a jet can't travel a parsec in 30 seconds.
posted by ikkyu2 at 1:43 PM on March 24, 2008


Heh, this post was like a magnet for pedants.
posted by vacapinta at 1:55 PM on March 24, 2008


Takes one to know one, vacapedant.
posted by ikkyu2 at 6:52 PM on March 24, 2008


my nose just totally went over and smelled a fart at its source. 30 fart-seconds away.
posted by joeblough at 7:07 PM on March 24, 2008 [1 favorite]


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