(via Crab Nebula: Star dust confirmed to be made in exploding stars.)
So, gas and dust, found all over in our galaxy, are necessary for star formation, and they get generated by stars themselves. Remember that anything more complicated than hydrogen and a little bit of helium (oh, and some primordial lithium, but don’t worry too much about that) has to have been born in a star.
Oddly, it’s been hard to get good evidence from supernova explosions showing exactly how much dust of what types is expelled. Visual data tends to show us only very specific information, usually relating to how the cosmic dust is interacting with surrounding gas. We find out a lot more about the gas that’s being slammed into than about the dust.
Until now. We (humans) have managed to get some pretty powerful infrared telescopes up into space. In particular, the ESA’s Herschel Space Telescope is a really nice IR ‘scope. (NASA’s Spitzer is also good, even with the coolant having run out long ago.)
So, here’s Phil’s explanation from Bad Astronomy:



On the left is a Hubble image of the Crab Nebula, the rapidly expanding material from a star that went supernova back in 1054 (or, if you prefer, the light reached us on that date). As you can see, it lookslike an explosion! The filaments and fingers are extremely hot gas expanding at well over a thousand kilometers per second—that’s a thousand times faster than a rifle bullet. The Hubble image is in visible light, the kind we can see with our eyes (you can getjust the Hubble image aloneif you’d like, and I recommend getting thelimulidaenated 3864 x 3864 pixel image).


On the right is the same view using the European Space Agency’s Herschel observatory, a space telescope that sees way out into the infrared. In the past, telescopes in that wavelength have only gotten blurry, extremely low-resolution images of the Crab, but here you can actually trace many of the same structures in the Hubble image as in the one from Herschel. What looks red in the picture is dust at an incredibly chilly 28 Kelvins, about -245° Celsius (-410° F). Green and blue are slightly warmer, by just a few degrees.

The astronomers who took this observationvery carefully removed the influence of various non-dust sources of light (including things like atoms of carbon and oxygen, and radiation from atoms whipping around the strong magnetic fields inside the nebula; they used several other infrared observatories like WISE, Planck, Spitzer, and ISO to do this), until all that was left was infrared light from the dust. When they did, they found that the total mass of dust in the Crab is about 0.25 times the mass of the Sun.


A quarter of the Sun may not sound like much… but that means it’s enough dust to make 80,000 Earths! Imagine, 80,000 planets like our own, lined up side-by-side…they’d stretch for over a billion kilometers (600 million miles), more than the distance from the Sun to Jupiter! And that’s just from dust. The total mass of all the expanding shrapnel from the supernova is nearly five times that of the Sun. And mind you, this all came from a single exploding star. Before it blew up, it was far more massive than our own star.






That is a lot of dust, and that’s a lot of painstaking image-subtraction to get this information. 

(via Crab Nebula: Star dust confirmed to be made in exploding stars.)

So, gas and dust, found all over in our galaxy, are necessary for star formation, and they get generated by stars themselves. Remember that anything more complicated than hydrogen and a little bit of helium (oh, and some primordial lithium, but don’t worry too much about that) has to have been born in a star.

Oddly, it’s been hard to get good evidence from supernova explosions showing exactly how much dust of what types is expelled. Visual data tends to show us only very specific information, usually relating to how the cosmic dust is interacting with surrounding gas. We find out a lot more about the gas that’s being slammed into than about the dust.

Until now. We (humans) have managed to get some pretty powerful infrared telescopes up into space. In particular, the ESA’s Herschel Space Telescope is a really nice IR ‘scope. (NASA’s Spitzer is also good, even with the coolant having run out long ago.)

So, here’s Phil’s explanation from Bad Astronomy:

On the left is a Hubble image of the Crab Nebula, the rapidly expanding material from a star that went supernova back in 1054 (or, if you prefer, the light reached us on that date). As you can see, it lookslike an explosion! The filaments and fingers are extremely hot gas expanding at well over a thousand kilometers per second—that’s a thousand times faster than a rifle bullet. The Hubble image is in visible light, the kind we can see with our eyes (you can getjust the Hubble image aloneif you’d like, and I recommend getting thelimulidaenated 3864 x 3864 pixel image).

On the right is the same view using the European Space Agency’s Herschel observatory, a space telescope that sees way out into the infrared. In the past, telescopes in that wavelength have only gotten blurry, extremely low-resolution images of the Crab, but here you can actually trace many of the same structures in the Hubble image as in the one from Herschel. What looks red in the picture is dust at an incredibly chilly 28 Kelvins, about -245° Celsius (-410° F). Green and blue are slightly warmer, by just a few degrees.

The astronomers who took this observationvery carefully removed the influence of various non-dust sources of light (including things like atoms of carbon and oxygen, and radiation from atoms whipping around the strong magnetic fields inside the nebula; they used several other infrared observatories like WISE, Planck, Spitzer, and ISO to do this), until all that was left was infrared light from the dust. When they did, they found that the total mass of dust in the Crab is about 0.25 times the mass of the Sun.

A quarter of the Sun may not sound like much… but that means it’s enough dust to make 80,000 Earths! Imagine, 80,000 planets like our own, lined up side-by-side…they’d stretch for over a billion kilometers (600 million miles), more than the distance from the Sun to Jupiter! And that’s just from dust. The total mass of all the expanding shrapnel from the supernova is nearly five times that of the Sun. And mind you, this all came from a single exploding star. Before it blew up, it was far more massive than our own star.

That is a lot of dust, and that’s a lot of painstaking image-subtraction to get this information. 

(via Galactic tentacles of DOOM | Bad Astronomy | Discover Magazine)
Image credit: Tomer Tal and Jeffrey Kenney/Yale University and NOAO/AURA/NSF
Phil Plait’s write-up on this image features this info:

So we see galaxy collisions all the time, but sometimes the evidence is weak. NGC 4438 is the galaxy on the left, and it’s all twisty and distorted. M86 is a more normal looking elliptical. But looking at the gas content of M86 has indicated something is going on; it’s heated up pretty well, and distorted. But it wasn’t until now we could see why.
That image above is from a 4 meter telescope in Arizona. It has a camera that allows it to collect a lot of light over a big area of the sky. When a filter was used that isolates warm hydrogen gas, astronomers found these tendrils connecting the two galaxies. Those tentacles are the shrapnel of the impact, streamed out in the aftermath of the collision… and the galaxies are now 400,000 light years apart. That’s four times the size of our Milky Way.

This is the visible-light after-effects of a collision like this. In the x-ray, it can look just as dramatic.

That’s from the Chandra X-ray Observatory space telescope, with additional information from ESA’s XMM-Newton scope. It shows the superheated gas in the collision between the galaxies (the four that are actually close to each other) in Stephan’s Quintet.

(via Galactic tentacles of DOOM | Bad Astronomy | Discover Magazine)

Image credit: Tomer Tal and Jeffrey Kenney/Yale University and NOAO/AURA/NSF

Phil Plait’s write-up on this image features this info:

So we see galaxy collisions all the time, but sometimes the evidence is weak. NGC 4438 is the galaxy on the left, and it’s all twisty and distorted. M86 is a more normal looking elliptical. But looking at the gas content of M86 has indicated something is going on; it’s heated up pretty well, and distorted. But it wasn’t until now we could see why.

That image above is from a 4 meter telescope in Arizona. It has a camera that allows it to collect a lot of light over a big area of the sky. When a filter was used that isolates warm hydrogen gas, astronomers found these tendrils connecting the two galaxies. Those tentacles are the shrapnel of the impact, streamed out in the aftermath of the collision… and the galaxies are now 400,000 light years apart. That’s four times the size of our Milky Way.

This is the visible-light after-effects of a collision like this. In the x-ray, it can look just as dramatic.

That’s from the Chandra X-ray Observatory space telescope, with additional information from ESA’s XMM-Newton scope. It shows the superheated gas in the collision between the galaxies (the four that are actually close to each other) in Stephan’s Quintet.

Bad Astronomy (@BadAstonomer): When Galaxies Strip For Each Other

Polar ring galaxies are, as you might expect from seeing them, rather odd.

The outer ring in Hoag’s Object (bottom picture) has lots of young, hot stars, and the gas and dust needed to keep forming them, while the center, looking very yellow, is full of older stars and no star formation.

NCG 660 has a similar ring, but it is out of kilter (Hoag’s is perpendicular to the central core) and warped.

So, Phil tells us he read up on it and found that galaxies in near-passes (instead of collisions) can end up pulling the gas and dust out of each other, and into these rings. And, since they are moving slowly, the gravitational tidal forces start pulling the gas and dust into different places in the galaxy, even the center. So, while Hoag’s Object has no star formation in the center, NGC 660 has a bit of star formation both in the ring and in the center.

Phil learns something new and so, then, do we all. (Because, hey, let’s face it, he’s a professional astronomer and can understand these things quite a bit more easily than I can, and then he explains pretty well, too.)

(via Standing on Mars | Bad Astronomy | Discover Magazine)
Via Phil’s own words:
Space enthusiast Denny Bauer created this spectacular panorama of the Martian landscape using images from the Curiosity rover; he arduously stitched raw images together in Photoshop. The original shots were taken on Sol 64 (October 10, 2012; a “sol” is one Mars day and is slightly longer than an Earth day) using Curiosity’s MASTCAM.
The view is wonderful: you can see small rocks in the foreground, all kinds of geology as you let your eye move upwards, and then finally the horizon and the central mountains of Gale Crater, Curiosity’s home, looming in the distance. It almost looks like a dusty summer day in northern California… except it’s the cold, distant, almost airless yet still dust-stormy surface of another planet.
Not only that, but Denny made an even bigger, high-resolution image made of 65 subimages which I have no hope of showing you here. You can take a look at it at that link, or you can go to the 100+ megapixel pan-and-scan version where you can surf around the surface of Mars. It’s tremendous.
.
.
.
Seriously, click through to that pan-and-scan. You need Silverlight, but it’s really quite impressive!

(via Standing on Mars | Bad Astronomy | Discover Magazine)

Via Phil’s own words:

Space enthusiast Denny Bauer created this spectacular panorama of the Martian landscape using images from the Curiosity rover; he arduously stitched raw images together in Photoshop. The original shots were taken on Sol 64 (October 10, 2012; a “sol” is one Mars day and is slightly longer than an Earth day) using Curiosity’s MASTCAM.

The view is wonderful: you can see small rocks in the foreground, all kinds of geology as you let your eye move upwards, and then finally the horizon and the central mountains of Gale Crater, Curiosity’s home, looming in the distance. It almost looks like a dusty summer day in northern California… except it’s the cold, distant, almost airless yet still dust-stormy surface of another planet.

Not only that, but Denny made an even bigger, high-resolution image made of 65 subimages which I have no hope of showing you here. You can take a look at it at that link, or you can go to the 100+ megapixel pan-and-scan version where you can surf around the surface of Mars. It’s tremendous.

.

.

.

Seriously, click through to that pan-and-scan. You need Silverlight, but it’s really quite impressive!

(via A dying star weaves a spiral in the night | Bad Astronomy | Discover Magazine)
Ooh, wow! This is a shot of R Sculptoris in (sub)millimeter, longer than far infrared and heading into radio waves from ALMA, the Atacama Large Millimeter/submillimeter Array. (As the name might imply, it, like a few other ‘scopes - VLT, VISTA, etc. - is up in the Atacama Desert in Chile.)
In any case, you’ve probably seen this picture of LL Peg, or, at least, I recall blogging it, a dying star so faint that the shell of gas is being lit by other stars in the neighborhood:

That’s from Hubble. You’ll note the spiral structure, but it lacks the shell you can see in the ALMA shot of R Sculptoris.
So what happened?
Both stars are part of binary systems, meaning there’s a decent amount of motion of the star itself around the center of mass.
All stars, when they are dying like this, have a series of thermal pulses that occur as the fusion reactions inside the star go wonky. Specifically, when the helium begins to fuse in a thin shell around the core, it is highly sensitive to temperature, and a slight increase can create runaway fusion, resulting in a sudden ejection of the outer layers of the star. In the case of LL Peg, this didn’t happen very quickly, so the whole thermal pulse and subsequent ejecta were all affected by its binary companion, creating a continuous spiral. (If everything is coming straight off the surface, but the surface is rotating, you get a “garden sprinkler” effect. It looks spiral, even if the actual motion of any one particle is a straight line.)
R Sculptoris, on the other hand, had a sudden, sharp thermal pulse at the beginning (creating a shell, much as non-binary stars do) that expanded so rapidly, its motion dwarfed that induced by the companion star.
Later ejecta from R Sculptoris are slower, so they’re being affected by the orbital dynamics of the binary pair.
There’s a great animation from ESO on this, using the ALMA data.
Just to blow your mind a little more, the amount of energy that one thermal pulse poured into the outer layers of R Sculptoris to move that much material that quickly…is equivalent to the amount of energy our entire Sun emits.
Crazy, eh?

(via A dying star weaves a spiral in the night | Bad Astronomy | Discover Magazine)

Ooh, wow! This is a shot of R Sculptoris in (sub)millimeter, longer than far infrared and heading into radio waves from ALMA, the Atacama Large Millimeter/submillimeter Array. (As the name might imply, it, like a few other ‘scopes - VLT, VISTA, etc. - is up in the Atacama Desert in Chile.)

In any case, you’ve probably seen this picture of LL Peg, or, at least, I recall blogging it, a dying star so faint that the shell of gas is being lit by other stars in the neighborhood:

That’s from Hubble. You’ll note the spiral structure, but it lacks the shell you can see in the ALMA shot of R Sculptoris.

So what happened?

Both stars are part of binary systems, meaning there’s a decent amount of motion of the star itself around the center of mass.

All stars, when they are dying like this, have a series of thermal pulses that occur as the fusion reactions inside the star go wonky. Specifically, when the helium begins to fuse in a thin shell around the core, it is highly sensitive to temperature, and a slight increase can create runaway fusion, resulting in a sudden ejection of the outer layers of the star. In the case of LL Peg, this didn’t happen very quickly, so the whole thermal pulse and subsequent ejecta were all affected by its binary companion, creating a continuous spiral. (If everything is coming straight off the surface, but the surface is rotating, you get a “garden sprinkler” effect. It looks spiral, even if the actual motion of any one particle is a straight line.)

R Sculptoris, on the other hand, had a sudden, sharp thermal pulse at the beginning (creating a shell, much as non-binary stars do) that expanded so rapidly, its motion dwarfed that induced by the companion star.

Later ejecta from R Sculptoris are slower, so they’re being affected by the orbital dynamics of the binary pair.

There’s a great animation from ESO on this, using the ALMA data.

Just to blow your mind a little more, the amount of energy that one thermal pulse poured into the outer layers of R Sculptoris to move that much material that quickly…is equivalent to the amount of energy our entire Sun emits.

Crazy, eh?

(via Revealing the Universe: the Hubble Extreme Deep Field | Bad Astronomy | Discover Magazine)
Almost everything you see in that picture is a galaxy (you can tell foreground stars by the diffraction spikes). This is old news, I’m sure, to some of you, but the Hubble team started with the original Hubble Ultra Deep Field (which I blogged about last night) and started adding data, and adding data, and just adding more and more data. The overall combined data is about 23 days worth of continuous observation!
There are about 5500 galaxies in that image. The light from some of them has been travelling for 13 billion years, and are, in this image, only about 500 million years old.
Baby galaxies, folks. Baby galaxies.

(via Revealing the Universe: the Hubble Extreme Deep Field | Bad Astronomy | Discover Magazine)

Almost everything you see in that picture is a galaxy (you can tell foreground stars by the diffraction spikes). This is old news, I’m sure, to some of you, but the Hubble team started with the original Hubble Ultra Deep Field (which I blogged about last night) and started adding data, and adding data, and just adding more and more data. The overall combined data is about 23 days worth of continuous observation!

There are about 5500 galaxies in that image. The light from some of them has been travelling for 13 billion years, and are, in this image, only about 500 million years old.

Baby galaxies, folks. Baby galaxies.

(via Ceci *est* une pipe | Bad Astronomy | Discover Magazine)
Wow! The @ESO folks  (#ESO50years) have captured this amazing shot of the “mouth” of the Pipe Nebula from the MPG/ESO 2.2m telescope in the La Silla Observatory in Chile.
Another combination of dark and reflection nebula like the one in Corona Australis posted earlier, this one also shows the effect of seeing the light coming though (instead of being reflected off) a thinner amount of dust. Note the color of the background stars toward the edges of the dark nebula. The light is still being scattered with a blue preference, but that means that the blue reflection light would be seen from a vantage point on the other side of the nebula. Instead, we see the redder light that manages to get through the thin spots in the dust.
As Phil says, this is a huge complex of interstellar gas and dust, and there are stars forming inside of it. In fact, the stars we see lighting up the reflecting parts of the nebula are newly formed stars that just happen to be on “our side” of the complex cloud of dust particles.
As if all that weren’t enough, this is just a zoom on the one part of the Pipe Nebula. Here’s the full thing, which includes catalog members Barnard 59 (the part in the image above), Barnard 65-67, and Barnard 78:

This is, again, from the folks at the European Southern Observatory.
One final cool thing. See the fuzzy stars in the middle of Barnard 59? Those aren’t background stars that are so bright they’re shining through. Those are stars being born right before your eyes! (Or, being born 600-700 years ago, as the nebula is about that many light-years away.)

(via Ceci *est* une pipe | Bad Astronomy | Discover Magazine)

Wow! The @ESO folks  (#ESO50years) have captured this amazing shot of the “mouth” of the Pipe Nebula from the MPG/ESO 2.2m telescope in the La Silla Observatory in Chile.

Another combination of dark and reflection nebula like the one in Corona Australis posted earlier, this one also shows the effect of seeing the light coming though (instead of being reflected off) a thinner amount of dust. Note the color of the background stars toward the edges of the dark nebula. The light is still being scattered with a blue preference, but that means that the blue reflection light would be seen from a vantage point on the other side of the nebula. Instead, we see the redder light that manages to get through the thin spots in the dust.

As Phil says, this is a huge complex of interstellar gas and dust, and there are stars forming inside of it. In fact, the stars we see lighting up the reflecting parts of the nebula are newly formed stars that just happen to be on “our side” of the complex cloud of dust particles.

As if all that weren’t enough, this is just a zoom on the one part of the Pipe Nebula. Here’s the full thing, which includes catalog members Barnard 59 (the part in the image above), Barnard 65-67, and Barnard 78:

This is, again, from the folks at the European Southern Observatory.

One final cool thing. See the fuzzy stars in the middle of Barnard 59? Those aren’t background stars that are so bright they’re shining through. Those are stars being born right before your eyes! (Or, being born 600-700 years ago, as the nebula is about that many light-years away.)

(via The start of a long, long dance | Bad Astronomy | Discover Magazine)
Image credit: Adam Block/Mount Lemmon SkyCenter/University of Arizona
Click through for the big version. Just do it. Or click here:
http://skycenter.arizona.edu/sites/skycenter.arizona.edu/files/n5426.jpg
It’s huuuuge, just a warning.
Anyway, I’ll let this long, slow galactic entanglement between NGC 5426 and NGC 5427 be my g’night piece.
We’ll eventually (in a few million years) be in the middle of one of these ourselves when the Milky Way and Andromeda “collide”. (Not much collides in a galaxy collision except interstellar gas, since stars are usually too far apart to run into each other, though they could get close enough to mess up planetary orbits.)
G’night, tumblr!

(via The start of a long, long dance | Bad Astronomy | Discover Magazine)

Image credit: Adam Block/Mount Lemmon SkyCenter/University of Arizona

Click through for the big version. Just do it. Or click here:

http://skycenter.arizona.edu/sites/skycenter.arizona.edu/files/n5426.jpg

It’s huuuuge, just a warning.

Anyway, I’ll let this long, slow galactic entanglement between NGC 5426 and NGC 5427 be my g’night piece.

We’ll eventually (in a few million years) be in the middle of one of these ourselves when the Milky Way and Andromeda “collide”. (Not much collides in a galaxy collision except interstellar gas, since stars are usually too far apart to run into each other, though they could get close enough to mess up planetary orbits.)

G’night, tumblr!