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Watch the Crab Nebula Expand Over a 13 Year Period

timothy posted about 8 months ago | from the imagine-the-world's-largest-crab-rangoon dept.

Space 65

The Bad Astronomer writes "A thousand years ago, the light from the explosion of a massive star reached the Earth. We now call this supernova remnant the Crab Nebula, and a new image of the Crab taken by astronomer Adam Block shows the physical expansion of the debris, made obvious in a short video comparing his 2012 observations with some taken in 1999. The outward motion of filaments and knots in the material can be easily traced even over this relatively short time baseline."

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LAME!!! just 2 exposures (3, Insightful)

Anonymous Coward | about 8 months ago | (#44447739)

LAME!!! just 2 exposures alternating back and forth.

Re:LAME!!! just 2 exposures (0)

Anonymous Coward | about 8 months ago | (#44447911)

Can't wait for the next 13 year sequel, it will be a blast !

Re:LAME!!! just 2 exposures (3, Insightful)

SlayerofGods (682938) | about 8 months ago | (#44447941)

Plus the biggest changes seem to be in the colors not the growth which might be related to the fact it was taken by two different telescopes....

Re:LAME!!! just 2 exposures (0)

Anonymous Coward | about 8 months ago | (#44448419)

Not really. As the nebula expands it will cool. Over time it will become even more red than it is now. That is the ionized hydrogen emitting light. It will be the last thing to cool below a point of emission. In the earlier picture you can see that many elements were emitting light over a larger spectrum than it is today. Those sky blue sections you see are the previously emitting elements now refracting light. Blue in color because of how easily that wavelength refracts, just like it does in our atmosphere.

Re:LAME!!! just 2 exposures (0)

Anonymous Coward | about 8 months ago | (#44450157)

I'm not sure if any of the parts of the parent's post are correct. Hydrogen won't be the last element to emit as it cools, as there are plenty of lower energy transitions in other elements, and even many elements there with lower ionization energies (e.g. iron and carbon). There are plenty of blue oxygen and iron lines that can be quite bright, especially if the gas is not in a thermal equilibrium due to ionization from emissions from the pulsar in the center. Additionally, the blue glow is not from Raleigh scattering in the sky, but has been shown to be synchrotron radiation from high speed electrons being stopped as they hit more dense plasma and gas.

Re:LAME!!! just 2 exposures (1)

cjjjer (530715) | about 8 months ago | (#44449861)

This is what I thought of, basically the newer telescope probably has updated optics and can take a finer grain of image, of course it will show more and seem like it has grown bigger.

Re:LAME!!! just 2 exposures (1)

thegarbz (1787294) | about 8 months ago | (#44452805)

No. Firstly the colours are simply mapping different emissions to different wavelengths. The reddish picture is what it really looks like with the red being mostly Hydrogen Alpha and in part Ionised Sulphur emissions (both infrared). The yellowish picture maps Hydrogen Alpha to the green channel and Sulphur II to the red channel (result is yellow / brown). In either case the blue remains Ozone emissions. This has been labelled the Hubble Palette as that's how pictures came from the Hubble so you could separate the amount of Ha and SII in each nebula rather than mushing them all into red.

But really note that the stars don't move, however the actual details like the shock fronts visible in the detail actually seem to move out from the centre. The colour, camera quality, and even exposure is really irrelevant. You could have seen the same result on a well calibrated backyard telescope and a DSLR if someone was looking.

Re:LAME!!! just 2 exposures (2)

tibit (1762298) | about 8 months ago | (#44450585)

Why the misinformation?! The background stars don't move, the nebula expands, the color is irrelevant. Watch it in black and white if you must.

Re:LAME!!! just 2 exposures (0)

Anonymous Coward | about 8 months ago | (#44452655)

There is a pretty wide variation in density, temperature and ionization across the nebula and its structures, which results in quite a variation in the emission spectra of different parts. The result is that you could take two different pictures at the same time, using different filters, and you can potentially see different parts of the nebula, and the size will look different as a result. There does looks like there is some clear movement of some structures, but that doesn't mean the color is irrelevant.

Re:LAME!!! just 2 exposures (1)

thegarbz (1787294) | about 8 months ago | (#44452825)

It does in this case. Red in the normal sense is Hydrogen Alpha and Ionised Sulphur when picked up on a colour camera. When narrow band imaging and mapping the emissions to the Hubble palette Hydrogen Alpha becomes green and Ionised Sulphur stays mapped to red. The result is that the red in the second picture is the same emissions as the yellow/brownish colours in the first pictures, and they clearly show expansion.

Re:LAME!!! just 2 exposures (0)

Anonymous Coward | about 8 months ago | (#44452893)

I think you missed the point. The ideas that there is visible expansion and that the details of filters (i.e. color) used is relevant, are not mutually exclusive. It is easily quite possible for different filters to produce the illusion of expansion, which is not the same as saying this image does not show expansion.

If someone says, "the colors look different, maybe these images were taken differently," the incorrect response is to say, "But the stars don't move and color is irrelevant." Of course the stars won't move if using different filters, that isn't a counter point to the idea they may have been filtered differently. Instead he could have said something closer to what you said, that in this case the colors are produced by very similar filters (disregarding that mapping them to different color channels will confuse some people more than others...).

If someone demonstrated an "anti-gravity balloon" and someone asks if it is filled with helium, you don't tell them, "It doesn't matter what a balloon is filled with," instead of maybe explaining in that case it was in a vacuum and that didn't matter in that case.

Re:LAME!!! just 2 exposures (0)

Anonymous Coward | about 8 months ago | (#44453165)

That could have been made more clear in the article, which briefly mentions using different filters, and links to the details of one photo, but not the other (unless I missed a link). Considering how often pop-sci explains or shows off images of other parts of the spectrum by contrasting them with visible images or different colors, some people are probably used to the idea that different colors (especially in false color cases, which are not always immediately obvious) or filters means things can look different. It is a perfectly relevant question or thing to consider, and is not resolved by looking at the lack of star movement or "watching it in black and white."

I wished people would ask more questions like that in my field of study, instead of just oohing and ahhing, or worse, chiding others for bringing up an important point to consider, even if it ends up not relevant to the particular example.

Re:LAME!!! just 2 exposures (0)

Anonymous Coward | about 8 months ago | (#44452711)

If you think color doesn't matter, compare this image [vstobservatory.net] with this image [vstobservatory.net]. They were both taken over the same nights in February 2008, but the latter has an H-alpha layer added in. There are stars in the former that look like they are outside the edge of the nebula, but in the latter now look like they are shining through part of the nebula.

Re:LAME!!! just 2 exposures (1)

thegarbz (1787294) | about 8 months ago | (#44452835)

The colour has nothing to do with being two different scopes. It's to do with two different ways of mapping data. The reddish picture is what the nebula looks like on a colour camera. Ha and SII emissions from nebula are infrared and cameras map them to red. When doing narrow band imaging if you want to separate these emissions you can do it quite well the way Hubble did and map Ha to the green channel and SII to red.

This means the yellow in the first picture is the same emission as the red in the second picture, and take a look at the shock fronts in both frames and note that they have moved outward from the centre.

Re:LAME!!! just 2 exposures (0)

Anonymous Coward | about 8 months ago | (#44452953)

H-alpha is pretty solidly within the visible range, and the sulfur lines at 671 and 673 should be visible to nearly everyone. And it is pretty vague to say what a "color camera" does with infrared, as it depends on what particular filters they used. In my experience, near IR stuff tends to show up on many cameras as either white or in the blue channel, even down to ~800 nm part of the spectrum. This experience has comes from having used many consumer cameras as a cheap alignment tool for IR optics, and they seem to have surprising half-assed ways of filtering IR some times.


Anonymous Coward | about 8 months ago | (#44447815)

And that was the end of that one !!

Nice shots (4, Insightful)

jfdavis668 (1414919) | about 8 months ago | (#44447861)

The newer one picks up more of the blue, so it looks larger. If you watch the red, it is definitely moving outward. Will have to use this the next time I teach about nebula.

Neat stuff, but... (0)

quintus_horatius (1119995) | about 8 months ago | (#44447871)

The video was over a minute, watching two images flip back and forth every couple of seconds with cheesy music in the background.

No voice over, no explanation, no real utility to the video. Showing the two static snapshots in a super-imposable way would have been a cooler use of technology.

Re:Neat stuff, but... (0)

Anonymous Coward | about 8 months ago | (#44447969)

be glad they didn't make a 10 hours youtube loop

Re:Neat stuff, but... (1)

vux984 (928602) | about 8 months ago | (#44449309)

be glad they didn't make a 10 hours youtube loop

Yeah, I've seen those in search results frequently... who does that and what ever for?!

Re:Neat stuff, but... (0)

Anonymous Coward | about 8 months ago | (#44449445)

for the lulz, mang, for the lulz! whats not to love about 10 hours of nyan cat or epic sax guy?

1054 (2)

war4peace (1628283) | about 8 months ago | (#44447953)

The Crab Nebula exploded in 1054; well, 6500 years earlier, to be pedantic. But the light arrived to Earth in 1054. So what else happened in 1054? Oh yeah, the great Schism (http://en.wikipedia.org/wiki/East%E2%80%93West_Schism#Mutual_excommunication_of_1054).
Funny coincidence...

Re:1054 (3, Insightful)

Anonymous Coward | about 8 months ago | (#44448413)

Ahh yes, a couple of loud mouth idiots from a church yelled at a couple of loud mouth idiots from another church, imagine that! Such a coincidence this happened at the same time as the Crab Nebula exploding.

Re:1054 (0)

Anonymous Coward | about 8 months ago | (#44449735)

Technically it happened about 6,500 years after the Crab Nebula exploded

Nobody on Earth knew until those loud mouth idiots yelled at each other, or, perhaps, when the sky lit up for a few days, those loud mouth idiots started yelling at each other (which is GP's point)

Re:1054 (1)

war4peace (1628283) | about 8 months ago | (#44450019)

Exactly. I was trying to be funny but apparently I was too subtle, so here's the "Redneck Joe" joke:

A star exploding 6500 years ago caused, through its light, Christianity to also explode in 1054.

Re:1054 (1)

Opyros (1153335) | about 8 months ago | (#44452767)

Yet, oh God, there were so many stars you could have used. What was the need to give these people to the fire, that the symbol of their passing might shine above the Great Schism?

Re:1054 (1)

arth1 (260657) | about 8 months ago | (#44453419)

The Crab Nebula exploded in 1054; well, 6500 years earlier, to be pedantic.

No, if you're truly pedantic, you point out that it took the photons 0 seconds from the explosion until they reached us.
There are no 6500 years that had passed because there's no common frame of reference and clock for the 6500 years to have passed in. 6500 light years is a distance, not a time, and calculating the time with the Newtonian approach of t=v/s doesn't work when the Lorenz factor becomes significant. At c, it's infinite.

And if you want to go full Albert, you'd say that it explodes in 1054 AD earth spacetime, at a vector 6500 light years distant.

Re:1054 (0)

Anonymous Coward | about 8 months ago | (#44462267)

There are no 6500 years that had passed because there's no common frame of reference and clock for the 6500 years to have passed in.

Actually there is a pretty reasonable assumed frame, the frame here on Earth. (While there are many different possible frames of reference of Earth, as far as relativistic effects, for lengths of time that long and with only a couple significant figures, they are all functionally the same.)

Re:1054 (1)

arth1 (260657) | about 8 months ago | (#44462769)

Actually there is a pretty reasonable assumed frame, the frame here on Earth.

Yes, and in that frame of reference, the star hasn't exploded yet in the year 1053 AD.
So there are no 6500 years that have passed, again because there's no frame of reference for that time to have passed in.

Re:1054 (0)

Anonymous Coward | about 8 months ago | (#44468043)

It would be pretty clear on a space-time diagram that the event happened 6500 years in the past. The projection on the time axis would be back then, as the projection on the space axis would be 6500 light years away. If you pick a particular frame, then things act much like they do in common, every day world. You can talk about things appearing simultaneously and what happened before what. Problems only come up with such an approach when trying to communicate between two different frames, where observers would disagree about things that normally seem impossible to disagree about if using pre-relativity thinking. Stuff like proper time was developed to give invariants that observers in different frames would agree on, but for a given specific frame, coordinate time works in the more mundane way, and simultaneity is parallel to the space axis, so the coordinate time of an event is not when its signal is received, but the time of when the signal is traced back to the source.

Bad comparison. (3, Informative)

EkriirkE (1075937) | about 8 months ago | (#44447971)

The second "larger" image was processed differently - more lightening of the dark end & over exposed. All the stars bloom in the new image as they've been enhanced stronger than the older image. Granted the internal filaments did move slightly, there is cheating to make it look more pronounced.

Of course, but... (4, Informative)

Gavin Scott (15916) | about 8 months ago | (#44448437)

Ignore the parts that are differently visible and the color differences, and focus on the parts that are the same in both images.

You'll see that the elements from the earlier photo have moved away from the center of the nebula and this is visible relative to all the background stars.


Re:Bad comparison. (1)

tuo42 (3004801) | about 8 months ago | (#44449025)

I agree to a degree (did I just type that?) that the comparison is not that good. The problem is: we are not only comparing eleven years in astrophotography experience, post-processing experience, post-processing software evolution, but also two completely different optical drivetrains if I understand the article correctly. Furthermore: different filters, different exposure times, different people doing them, different cameras and chips (or at least in different ages)....I could go on for a couple of hundred characters, everybody who does astrophotography knows what I mean. It would have been far more interesting to have the data of one of the channels (maybe L would be suited if the narrowband filters of both exposures differ too much. Should be enough to get an impression of the size differences) stretched to have the same curves, then registered, then blinking them. It also seems like both exposures used a different palette for the narrowbands. First looks kinda hubble-equse on some parts, while second looks very traditional (might even be L-RGB or - mind you - a modern OSC). In this case, it indeed looks like a non-ideal comparison. Without any details about both images (filters, exposure times etc.) it is hard to compare them. regards tuo

Re:Bad comparison. (1)

thegarbz (1787294) | about 8 months ago | (#44452869)

Without any details about both images (filters, exposure times etc.) it is hard to compare them.

Actually there's plenty to compare. The first picture and the second picture is recording the same structure just that yellow = red, and both emissions are Ha + SII. Now when you ignore the colour just look at the location of stars to identify your arc seconds per pixel, and then start measuring the internal parts of the nebula that moved.

All the information you need is there once you get over the fact that the pictures look different, just focus on the structure and pronounced features.

Re:Bad comparison. (2)

tibit (1762298) | about 8 months ago | (#44450625)

Many people keep repeating it. To me it seems to indicate that many people are either in serious need of an eye exam, or that they see only what supports their preconceived notions, not how it really is. There is no "slight" movement of the filaments, the images almost look like they were of different nebulas, if it wasn't for the background stars!

Re:Bad comparison. (1)

thegarbz (1787294) | about 8 months ago | (#44452847)

Can you really call a step change in performance between cameras of 1999 and 2012 cheating? This is really irrelevant as the only thing that matters is how many arc seconds wide the internal structures of the nebula are, and as you said the filaments did move I think you'll agree with me when I say if we used the same old camera we'd still end up with the same article showing the nebula expanded.

I'd like to look but... (1, Funny)

Kaenneth (82978) | about 8 months ago | (#44447985)

Cool guys don't look at explosions.

Re:I'd like to look but... (0)

Anonymous Coward | about 8 months ago | (#44449247)

I can't figure out which of the two dozen sites popping up in NoScript actually need to be allowed to view the frickin two-frame video.

Memorial (4, Funny)

slashmydots (2189826) | about 8 months ago | (#44448001)

We should all take this time to remember the brave folks who, thousands of years ago, had to self destruct their crab-class starship to save the universe from the Daleks.

I haven't got the patience for that! (-1)

Anonymous Coward | about 8 months ago | (#44448295)

Watching a nebula expanding for 13 years? That's worse than watching paint dry, or grass grow!

OTOH, it sounds like a good way to separate the fake Pinkie Pies from the real one.

mod 04 (-1)

Anonymous Coward | about 8 months ago | (#44448399)

Year contract. Against vigorous Good manners And was take8 over many users of BSD to avoid so as to To underscore

if you look carefully (1)

goffster (1104287) | about 8 months ago | (#44449023)

many features near the edge have not moved at all. It leads me to
think that in the later exposure, you are simply seeing details
that were not previously visible.

That site sucks (0)

Anonymous Coward | about 8 months ago | (#44449473)

You have to drop your pants on a few dozen dubious tracker URLs and then it's a Vimeo video which is served from a a potato-powered server someplace.

There are probably a million lines of JavaScript that want to execute so that I can see what *should* be a two-frame animated GIF with a direct link. Remember? Remember when it'd be an a .EDU server someplace, just like that?

Sheesh. Shit like this just makes me want to unplug the whole web. My machine is fully capable of viewing the video, but I'm not going to jump through these hoops just to view it. Will somebody please turn it into the aforementioned GIF and host it someplace with a direct link that isn't trying to monetize every damn cycle on my CPU?

Amazing Speed! (1)

neorush (1103917) | about 8 months ago | (#44449773)

Anyone figure out how fast the "debris" is moving from the center? To see this kind of a change, on this scale, in such a short time, it must be mind-blowing fast!

Re:Amazing Speed! (0)

Anonymous Coward | about 8 months ago | (#44451721)


WTF Slate? (2, Insightful)

wiredlogic (135348) | about 8 months ago | (#44449843)

Off topic but I really am annoyed with the hack web "programmers" that build web sites with a dozen or more cross site scripts. Here's the shit list from this latest atrocity:


That's 21 external javascript sites. There are probably more that would be pulled in if I enabled all these sites in NoScript. This is seriously pathetic.

Messier and M1 (2)

spaceyhackerlady (462530) | about 8 months ago | (#44450905)

I have heard it suggested that when Messier was compiling his list of things not to look at because they're not comets, the Crab Nebula was prominently in his list because it was significantly smaller and brighter in his day than it is now. It's far from conspicuous today...


Funny (1)

Iniamyen (2440798) | about 8 months ago | (#44451629)

There are more comments bitching about the link than comments about the actual nebula. Even the nerds are disinterested in space these days...

Re:Funny (1)

aiht (1017790) | about 8 months ago | (#44453593)

There are more comments bitching about the link than comments about the actual nebula. Even the nerds are disinterested in space these days...

No, it's just that the nerds who are interested in space already knew that this happens, so the only new thing here is the presentation.
I was a bit disappointed because I was expecting a time-lapse video.
I still think the video's worth watching, but switching between two images is hardly a revolutionary technique in astronomy.

After watching it... (1)

PJ6 (1151747) | about 8 months ago | (#44452765)

I'm overwhelmed with regret that they did not, indeed, take a picture every week like I expected, or even every year.

Two pictures. And they made a VIDEO. For two pictures.


I really think that THIS is far more impressive (1)

jkg2 (2751749) | about 8 months ago | (#44454455)

Hubble: Timelapse of V838 Monocerotis (2002-2006) [1080p] [youtube.com]
"The NASA/ESA Hubble Space Telescope has been observing the V838 Mon light echo since 2002. Each new observation of the light echo reveals a new and unique "thin-section" through the interstellar dust around the star. This video morphs images of the light echo from the Hubble taken at multiple times between 2002 and 2006. The numerous whorls and eddies in the interstellar dust are particularly noticeable. Possibly they have been produced by the effects of magnetic fields in the space between the stars." (apologies if this is a re-post)
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