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Supernova Imaged by Hubble Telescope
Delta Vel writes "First discovered by a Japanese amateur astronomer on July 31, this Type II supernova was imaged by Hubble on August 17th. The newly named SN 2004 dj, the closest supernova to be observed in over ten years, is about 11 million light-years away in the spiral galaxy NGC 2403. Looks like they goofed in one of the images, though--the arrow points to a different bright spot on the before-and-after image than it does on the main and annotated images." Reader Saeed al-Sahaf writes "Today, astronauts Gennady Padalka and Mike Fincke popped open the hatch on the Russian side of the ISS spacecraft and quickly stepped through the fourth and final spacewalk of their six-month mission. Their mission? Install three antennas and replace a 2-foot-square Russian pump panel. But of course, because it isn't a part or our Mission to Mars, it is still too dangerous work on the Hubble Telescope, which after all, is only used for science."
UC Berkeley's NewsCenter has a nice article about this. The astronomer is from UC Berkeley.
Google logs it just fine. The page uses frames, which your browser does not display due to the google-added header. Your browser also does not display the noframes content, as it does support frames.
It's all there, your browser just doesn't display it.
Try This.
That story regards NASA's tentative approval to design and send a robot to fix hubble, rather than simply sending over the shuttle.
Who said they could? Lol.
But seriously, I know the dynamic range of CCD's used telescopes can be at least 16 bits grayscale. To display them on a monitor/lcd you have to do some conversion. What basically look like very faint distinctions of shades of grey appear to be a detailed, crisp, starry picture of the sky to us (after conversion by the computer).
End result: They know that this white spec is ~100 times brighter than the white spec next to it, by looking at the raw intensity values observed from the camera.
p.s. Yes, I know that is a color image -- they probably took 3 grayscale images with red,green,and blue filters.
Not for the dialup dudes, but great for broadband buddies:
/ a/formats/full_jpg.jpg
http://imgsrc.hubblesite.org/hu/db/2004/23/images
...because it is in another galaxy.
If it were in our own galaxy then it would have a chance of being visible.
But even if you weren't sure, the "wavelength/frequency" of the light is INCREDIBLY different. A good eye can tell the difference between all the different sorts of supernova spectra in seconds.
Educated guess, my ass.
By the way, I'm one of Filippenko's supernova checkers. Hi everybody!
-Harrison
Quid festinatio swallonis est aetherfuga inonusti?
Africus aut Europaeus?
They arrows are fine... You just have to realize that the first images have the majority of the galaxy cropped out... They are only showing NGC 2403-1, instead of the large NGC 2403.
-Bill
Ok, I'll bite, rather than mod you -1 troll.
1) Age isn't necessarily a bad thing with a telescope. Lots of telescopes are a lot older than that - witness the Anglo-Australian Telescope, the UK Schmidt Telescope, and the recently burned-down Great Melbourne Telescope (aka MSSSO 50") which provided evidence that the universe is accelerating.
oh yeah, and hubble was launched on April 24, 1990 - you do the maths.
2) The replacement, the James Webb Space Telescope is optimised for the Infra-Red and can NOT operate in the blue/UV like hubble. Nor will it be launched until 2012, 4-5yrs *after* the prospective hubble death date.
JWST will also be at the L2 lagrange point, meaning that there is NO possibility of any servicing mission. here is info on the orbit.
3) There are NO better telescopes on the ground for imaging. Hubble has a *diffraction-limited* resolution of about 0.05" - 0.1" (0.05 - 0.1 arcsec). The BEST sites in the world (Mauna kea, cerro paranal) get seeing as good as 0.3-0.4" at the best of times, and that isn't too often.
No, adaptive optics do NOT help because they limit the field-of-view. Hubble has a diffraction limited FOV across the entire chip.
4) Hubble does not have to contend with atmospheric absorption, which makes observations in some bands (like the aforementioned UV) nigh on impossible.
Messier object 1 (M1), more commonly known as the Crab Nebula, is a good example of a "Long ago" supernova remnant.
Crab Nebula Info
The star went supernova almost a thousand years ago, and that is whats left.
During the actual event of a supernova, though, the star (from so far away) only seems to go from being a normal star to an amazingly bright one, and then slowly dimming down over a few months (or years). The reason is because stars are so huge they cannot simply explode like in the movies, after all they are in a constant state of nuclear fusion!!
-Bill
Type Ia supernovae take about a month to reach their peak brightness. While this is a Type II, a different class of explosion, I think the timescale is comparable. Accoring to this page the supernova had an apparent visual magnitude of 11.3 in early August. This is a factor of 100 dimmer than the naked eye can see under the best conditions (magnitude 6 is the dimmest the unaided eye can see).
If you're unsure of why a higher number means a dimmer object, or just want more information, czech out the Wikipedia entry on visual magnitudes.
By the way, the last supernova that was visible to the naked eye was SN1987A in the Large Magellanic Cloud.
I would rather be killed by a terrorist than enslaved by my government.
If it really appeared as bright as the sun, but was coming from a star-sized pinpoint in the sky, that might be a little hard on the retinas if you looked at it directly.
Now, in the event you notice that the entire upper atmosphere has been turned into an orange smog by the gamma rays, then you know that the supernova was really too close for comfort. In that case, head down to your basement for a few years until the ozone comes back.
The rate of occurrence of supernovae in our own galaxy is now reasonably well determined to be one every 25 years. Supernova remnants in our own Galaxy and nearby galaxies are theoretically observable for over a million years.
Bingo! Hubble takes grayscale pictures and these gets converted to false colour later. The reason? Hubble doesn't shoot with real colour because it would be useless for science. Instead, it uses some filters to pick up radiation from some certaion ionized atoms, hence HII (Hydrogen two) reference in the annoted picture. Now, looking at this picture, certain hue (like red) can represent HII. As a result, anywhere red occurs, you know there is lots of hydrogen. This helps with the amount of science can be obtained from a very pretty picture (after someone tweaks the colours to look pleasant for non-scientists).
Hubble Heritage Project is an awesome project and they should release more pictures. All of the HHP pictures are for real science but coloured for our pleasure as well. Hubble time is so rare and expensive, you can't waste it on snapshots.
If they weren't native, then probably they had the means of travelling between star systems, no contest, it's just like a huge Florida evacuation, only 14 million times larger. :-)
the neutrino pulse for 87a was seen hours before the optical observation.... http://zebu.uoregon.edu/~soper/StarDeath/sn1987a.h tml
- "Hear that?! The percolations are imminent! Cease your ingress!"
Actually our sun does not have enough mass to go supernova. A star needs a mass about 1.4 times our own for it to go supernova, and this is called the Chandra Limit.
According to current theory, our sun at the end of its lifetime (5 billion years from now) will become a red giant and throw off its outer layers forming a planetary nebula, and then turn into a white dwarf.
If, by chance the sun as a white dwarf is captured by another star's gravitation, it could draw off mass from that star and then go supernova.
If the sun were to turn into a variable star or nova between now and white dwarf stage, it could very easily boil away the oceans. Some scientists think that the sun will gradually increase in luminosity and that earth will be unhabitable in a billion years.
Alternatively, if a nearby star (25 light years away) were to go supernova, that would pretty much kill the ozone layer and the sun's UV would fry us.
Some scientists think that there is no life in the universe because supernova are such large events in galaxies that as life gets started somewhere it probably gets wiped out by a nearby star going supernova.
Take the cheese to sickbay, the doctor should see it as soon as possible - B'Elanna Torres, "Learning Curve"
There are plenty of stars just itching to blow, though. Eta Carinae is about ready to pop, and Betelgeuse isn't far off. Either of these stars blow, we'll have a hell of a show.
Real Daleks don't climb stairs - they level the building.
Close: it's the Chandrasekhar Limit.
It's not the star, but the core of the star that needs to exceed 1.4 solar masses. The Sun will eventually run out of hydrogen in its core, and fusion will end. The core will then be unsupported against its weight, and will contract and heat up dramatically. The increased heat will trigger nuclear fusion of helium, then the Sun switches on again. While the core's heating up, the increased temperature makes the outer layers balloon out to a huge volume, forming the red giant.
It's the core that's interesting, though. Eventually the helium runs out too, and we have a very dense gas of carbon. It contracts and heats up, but the Sun isn't big enough to reach carbon-burning temperatures. So the core can't support itself by burning to produce heat, and instead collapses until it's supported by 'degeneracy pressure' resulting from the fact that in quantum mechanics, no two electrons can occupy the same state.
The Chandrasekhar limit is the maximum mass that can be supported this way, and it's 1.4 solar masses. Get above that mass, the core of the dead star collapses, FAST. The next state down is the neutron star, held up by degeneracy between neutrons rather than electrons. All that matter falling at very high speed hits a core of hard neutronium and the fun starts. Lots and lots and lots of energy has got to go somewhere... the result being a star-shattering kaboom.
Real Daleks don't climb stairs - they level the building.
It looks cool and all, but theres an even bigger looking one to the left.
Yeah, that's a star. About 11 million light years closer than the supernova. Just to give a hint of a relative brightness...
How exactly can they tell the difference?
Well, dunno, if you don't want to hear anything about doppler and red shift or wavelength, how about the fact that the bright star has been there for as long as we've been looking whereas the supernova just popped to brilliance a few months ago from a location that did not have anything even remotely as bright before?
Also the neutrinos get out of the Supernova core instantly, whereas the energy that is going to come out in photons has to fight its way up through the upper layers of the star.
According to http://stupendous.rit.edu/richmond/answers/snrisks .txt, the kill radius for a supernova is around thirty light years. Beyond that, bad stuff happens, but less as the distance increases, and life would survive. Our satellites would probably all get toasted, though.
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In this case, the supernova was observed almost as soon as it was visible. We can tell, because we have amateur astronomer's images from just hours before the supernova exploded, and nothing out of the ordinary was there.
-aiabx
Just this guy, you know?