"At the last dim horizon, we search among ghostly errors of observations for landmarks that are scarcely more substantial. The search will continue. The urge is older than history. It is not satisfied and it will not be oppressed." -Edwin Hubble
Given the relative peace of our night skies, combined with the vast distances from our Solar System to the nearest star, we don't often think about the cosmic catastrophes that took place in our past. But these catastrophes are the very things that gave rise to our Solar System in the first place!
Yes, it's dense, cold, contracting gas -- enriched by previous generations of stars -- that gives rise to stars and planets like the ones found right in our own backyard. But the clouds of gas we find strewn throughout are galaxy, for the most part, are far too diffuse to simply contract down under the force of gravity to form all these new stars. It usually takes some sort of catastrophic event to set that off!
On very large scales, two large galaxies colliding together is one of the most spectacular examples of such a catastrophe. The closest galaxy to us in the process of colliding is the magnificent and unusual giant galaxy, Centaurus A, located just 11 million light years away.
Looking at this galaxy even in the above (limited) set of wavelengths shows us something remarkable. It has a diffuse, nearly spherical shape judging by its stars, reminiscent of an elliptical galaxy. But it also has a set of big, central dust lanes, just like we see from spiral galaxies. In fact, Centaurus A is actually two galaxies in the midst of merging: one thought to be a spiral and one thought to be an elliptical. Looking with a full set of visual wavelengths helps make that even clearer.
This is a very impressive image, no doubt, as you can see that the predominant color of the stars around the dust lanes are a bright blue. This contrasts with the rest of the galaxy's stars, which are yellower, and hence older. These young, blue stars tell us, unequivocally, that these are regions where new stars have just formed.
But, as you might have guessed from the title, even the best ground-based image still can't hold a candle to the spectacular imaging power of the Hubble Space Telescope. What do you suppose it saw when, last year, it turned its attention towards Centaurus A?
As you might have guessed, not having an atmosphere to contend with greatly amplifies the resolution at which you can take images. And this Hubble image -- if you want to see the really high-quality version -- can show you not just the bright blue stars, but the red, ionized emission nebulae, the collapsing cold dust, as well as the diffusing, evaporating areas. Here's just a tiny section from that super high-quality image.
Remember, this galaxy is eleven million light years away, and you can image individual stars in it! This type of interaction -- a major merger between two relatively large galaxies -- can produce upwards of a thousand stars per year, more than 100 times the rate they're produced in our own galaxy. Over the duration of just a few million years, literally billions of stars can form from a collision like the one Centaurus A is experiencing. Thanks to the Hubble space telescope, we get an unparalleled view of the formation of these new stars.
But without prior generations of stars that have lived, burned their fuel, and polluted the intragalactic gas with heavier elements, none of those stars could ever have rocky planets orbiting them. Unbelievably, Hubble's got us covered there, too.
Whether it's a star like our Sun, that will die in a planetary nebula, like the helix nebula, above, or a much more massive star, that blows off its outer layers in a supernova explosion, these stellar corpses are the sources of all the common heavy elements in the Universe, from Carbon, Nitrogen and Oxygen up through Neon, Silicon, Sulfur, Iron, Nickel, Cobalt and more, all of these elements come from the ejecta from deceased stars. Sun-like stars that die in a planetary nebula can have a roughly spherical end to their life, like the Helix Nebula, above, or a more bipolar structure, like the Butterfly Nebula, below.
The expelled gas from these regions enriches the interstellar medium, but it can also run into these diffuse, massive gas clouds that move through our galaxy. Collisions, under the right circumstances, can trigger the process of star formation in these clouds, leading to a beautiful star-forming region, like Sharpless 2-106, below.
Indeed, in term of resolving power, depth, and clarity, no telescope on Earth can rival the images Hubble produces.
But it gets even better than this!
You see, Hubble isn't the only telescope that's looked at these objects, it's just the best one. By looking at different wavelengths of light, measuring doppler shifts of the outflows, and imaging from multiple locations in space, they were able to infer and construct models of the full, 3-D structure of these objects. Ever wonder what it would be like to fly around a star, not unlike our Sun, as it goes through the final phases of its death? Check out this fly-through of the Helix Nebula. (It takes about 25 seconds to get going, so be patient!)
How about the Butterfly Nebula, where the gas flows outwards from the central region at speeds topping 600,000 miles-per-hour?
Or, as perhaps the best Hubble video ever could show you, take a tour of the star-forming region Sharpless 2-106.
Around four-and-a-half billion years ago, a region of our Milky Way not unlike this one gave birth to the star and planet we call home. When we examine a region like this, we're examining our own origins -- the birth of the Sun and the Earth -- as much as anyone possibly can.
Yes, these videos also involve a bit of artistic license; there is only so much we can learn from thousands of light years away, but these are the most scientifically accurate visualizations we can possibly construct. And we can only do it thanks to Hubble: still unbeatable after all these years!
(Thanks to DJ Busby at Astronasty for finding these videos; there's one more over there to see for the curious!)
Request for post:
Over the Christmas break (or just before) two pieces of news came out of the LHC.
First, the initial data on the Higgs, which was covered by a detailed post.
Second, the confirmation of a new particle (chi b(3P)), which was not mentioned on the blog.
Is there something to write home about?
Great post - thanks. :-)
Wonder if someone could /already has turn those animations of travelling into the Helix planetary, Butterfly nebula and Sharpless 2-106 into screen savers? [*Want*]
Great quote there too btw. Where do you find 'em?
Hubble is still umnbeatable FOR NOW; but I can't wait. And not just for the James Webb Space Telescope.
"Consortiums Compete to Build World's Biggest Telescope. A telescope arms race is taking shape around the world... the super-sized telescopes will yield even finer pictures than the Hubble Space Telescope... some astronomers worry that there may not be enough private or government money for all of them, so they find themselves competing for funding, even as they cheer each other on." http://www.foxnews.com/story/0,2933,328381,00.html
Current land based telescopes "are able to look back only about 1 billion years in time. But the new telescopes will be so powerful that they should be able to gaze back to a couple of hundred million years after the Big Bang, which scientists believe happened 13.7 billion years ago." (very nice).
And by the way a land based telescope cost $500 million to $1Bil plus versus the James Webb (as well as the Hubble's) $5 to $10 Billion.
So do we need to see 13.7 billion lightyears away, giant asteroids, exoplanets and more? Yes, yes. Need? Yes, yes need; man does not live by sushi alone.
Of course there is probably some top secret military research using these astronomical technologies in reverse. Yes to peer through the Earth's atmosphere from spy satellites and get unprecedented clear images of whatever.
So per Ethan's post of a few days ago, write your Senators and Congressmen to fund necessary land based astronomy.
Read Ethan's recent "Are we trading away the education of future astronomers?" post too. My comments here and @4 above are a continuation from there.
1) Telescope costs at the very highest end have dropped from $10 Billion (i.e. the Hubble space telescope)telescope) to $1 Billion for an equivalent land based telescope (i.e. The Giant Magellan Telescope, The Thirty Meter Telescope, The European Extremely Large Telescope). WHOA!!!!
2) Current land based telescopes can see only 1 billion lightyears; but new ones (e,g, The Giant Magellan Telescope) will see objects 13.7 billion lightyears away. (very nice)
So my questions???
1) Can medium sized new technology telescopes be built and operated at modest price ($10 to $100 mill vs $1 bil) that are capable of seeing 2 to 5 billion light years away? Because such instruments could do a lot of excellent science and employ a lot of excellent scientists.
2) Or, is astronomy doomed to be a superbig science like elementary particle physics where only super instruments (e.g. CERN) can do leading edge science?
3) What very difficult astronomic research (e.g. in the 2 billion lightyear range) might not get telescope time on an instrument capable of 13.7 billion lightyear clarity.
I oversimplify of course; so please educate me. Thanks.
Don't want to criticize---like who am I, sort of, but....
Having layman experience of photography and using the first PC multi-layer graphics some 30 years ago, feel your favorite was not my favorite. To me a static shot on the object, some sliding (panning---to creat 3-D illusion) of background stars. Could see no development in time. Don't feel the parallax effect due to Hubbles change in position would be this great to move the background stars this much---but that's a technical reservation, not an illusional one.
My favorite was the Helix Nebula. Particularly, the (for drama?) lack of development in the beginning which increases anticipation and then the swooping orbital pan revealing the spherical form finally. Epiphany.
Thanks a million. To you and them.
I wrote the President about the matter with underfunding of "training" observatories, particularly pointing out the Nobel Prize connection. He hasn't answered yet. He never has so far!? Wonder why?
Lastly, for those wanting the Butterfly, as far as I can see, the still (not video) posted here is the same as I have used on my laptop. Just right-click and choose the right option.
You make astronomy/physics and the lack of teleology fascinating. We are so small. Wonder why some can't accept that?
OFF TOPIC QUERY
You mention element generation through supernovas.
Considering that 99.9% of the energy produced is emitted as neutrinos (except type 1A), what is the "purpose" of them in cosmological terms? Speed of light, practically no mass, no interactivity (or very little). So why bother?
I know, it doesn't work that way, But much ado, but no effect?
Lastly, have never seen a placement wavelength-wise of neutrinos. Can GeV be converted to frequency or wavelength.
Or in comparison to hard X-rays?
I have a question about planetary nebula. There are objects around the periphery of the central gas bubble in NGC 7293, and made especially visible in the animation you shared. They look like comets or Kuiper belt objects that have long tails - perhaps atmosphere or surface ice that has been evaporated and swept away by the speeding gas of the nebula. Actually there are two similar phenomena shown in this animation - objects inside of the blue inner bubble, whcih seem to be distributed evenly through space at a certain distance from the star, and objects in the orange outer cloud, which seem to be limited to a disk, which I would guess is in the plane of the star's planetary disk. These can be seen in many planetary nebula and I wish I knew what they were. Have astronomers ever located any extrasolar planets in planetary nebula? I don't know much about the scale in these images - perhaps these things are too far out be Plutoids? How big is one AU in this image? Perhaps the streaks are merely emergent patterns in the fluid dynamics of the solar wind? And I wonder whether these objects, if they are objects, remain gravitationally bound to their central star after such a mass-reducing explosion. If not, are there a great number of rogue bodies such as these drifting through interstellar space? Have astronomers ever determined than any extra solar bodies such as these have entered our system or even become gravitationally bound to our sun?
Daily lurker wishing you all the best in the new year. Thank you for the noble education efforts.
Happy New Year and best wishes and thanks for your fascinating blog!
I'm a biologist, not an astronomer but I've always loved this subject. However, viewing the photos and especially the videos, I've been often bothered by my own lack of "sensawunda" and I think I've identified why: My mind can't grasp the scale. And in images, it's the stars. When we are "moving" through a star field, say, toward a nebula beyond, the stars seem to move about like the objects outside my car windows do. Some move quickly past, like the beer can in the gutter only inches from my wheels; some move more slowly, like the swingset in the yard of a house I'm passing; some move more slowly, like the village water tower on the edge of town; and some move glacially, like the mountains I can see thirty miles beyond the town I'm passing through. THOSE scales I "get," they're commonplace. But my understanding of stars tells me that even the closest-together of those stars are MILLIONS of miles apart, else their enormous masses would tear one another apart. My brain just cannot put those stars, moving in what appear to be familiarly varying speeds, into any distance context. Is there any help for this? My eyeballs LOVE these images but my "sensawunda" organ remains unstimulated.
In the Helix and Sharpless videos what would you estimate the observer's velocity to be (with ramifications for the appearance of the two objects)?
Are you asking me? In case you are, I'd have to say that appears to be part of my problem - I can't grasp what speed we're "moving" in those videos. It *feels* like oh, 55 mph. LOL
@12 Was asking the author, but knowing that the speed of light must be exceeded eg a 15 second scaled zoom from sun to earth would represent 32 times light speed.
*sigh* Another Big Thing I can't seem to get my head around.