Follow the Pointer

A wide-field image of WR-25 and Tr16-244 in the Carina Nebula. Courtesy NASA/ESA Hubble Space Telescope.

My friend Phil Plait has a thing about instances of pareidolia — the tendency of humans to see interesting patterns in things.  It’s a peculiar psychological thing that our primate brains do to us when we see things we don’t immediately understand or can’t place in context. So, for example, you look up at clouds in the sky and see spaceships or dogs playing or sheep sleeping or whatever it is that the cloud seems to resemble. And, of course, there are tendencies among some folks to see things like faces of deities in toast and tortillas, or peeling paint, or the bark on trees. It’s all very amusing and shows you how complex our brains are.

Astronomy images provide hours of merriment for pareidoliacs.  Take this picture, for example.  It’s a Hubble Space Telescope view of a gas and dust cloud where star formation is taking place. Notice in the very top of the picture that there’s a thick cloud of dust in the shape of a pointing finger. At least, that’s what it looks like to me.  And, it  might appear that way to you, too.

Well, you might ask — what’s it pointing to?  Good question, and the answer is what the subject of the image really is:  a pair of massive bright stars down in the lower third of the image that are shining out like a pair of headlights. (Or, if you’re a fan of LOLcats, they look like “cat lazors” charging up.)

This scene is smack in the middle of the Carina Nebula, a huge region where clouds of gas and dust are combining to form new stars. It is about 7,500 light-years away from us, and also contains the luminous blue variable Eta Carinae, which is expected to pop off as a supernova pretty much any time now (in cosmic terms).

It turns out those two bright stars have an interesting connection to the pointy-finger cloud. The bright star in the lower center is called WR-25, and its quite massive — more than 50 times the mass of our Sun.  In fact, it’s really two stars orbiting a common center of mass. They hot, bright, and interacting with each other.

The star to the left of WR-25 is called Tr16-244, and it’s actually three stars orbiting a common center of gravity — a triple-star system. Together, these two star systems are eating away at the clouds of gas and dust. That “cannibalization by radiation” is actually what sculpted the finger-shaped cloud. It’s amost as if the cloud is pointing the finger of blame back to the stars that shaped it — a nice case of cosmic pareidolia.

Wearing Ultraviolet Swim Goggles

It's Galaxies (nearly) All the Way Out! (Click to embiggen)

This is a region of space called the Chandra Deep Field-South, a region of the sky that fascinates astronomers so much that it is one of the best-studied in the whole sky. Over the past few years and into the future, astronomers have been and will be concentrating on this region and one other in the northern sky as part of the GOODS survey, to do the deepest, most sensitive observations they can with every observatory on the ground and in space, in every wavelength possible.

The European Southern Observatory’s Very Large Telescope took its turn, along with the 2.2-eter MPG/ESO telescope. Together they gazed for 55 hours, using the ultraviolet-sensitive VIMOS instrument on VLT and the Wide-field Imager on the MPG/ESO telescope at La Silla.

They announced the result today: a 27-million-pixel-wide image that shows a  pool of galaxies, many of them appearing as they were when the universe was only 2 billion years old.  These most distant galaxies are a billion times fainter than the unaided eye can see, and not easily visible to optical instruments. Ultraviolet-sensitive instruments like VIMOS (which focused on wavelengths of light in a range between UV and optical), when used in longer exposures, can catch enough of the light from these distant galaxies to reveal them for us to see.

Nearly everything you see in this image (with the exception of a few bright stars in the foreground (part of the Milky Way Galaxy) is a galaxy. Each of those galaxies has billions of stars.

Now, here’s a thought-provoking idea to chew over while you gaze at this picture:  the universe looks the same no matter what direction we look in — that is, it has a roughly similar distribution of structure (galaxies and clusters of galaxies) in all directions.  This means that if we could point telescopes in all directions of the sky (without interference from the Milky Way) the distant universe would look like this all over the sky. Think about it–countless millions or billions of galaxies… some dating back to the childhood of the cosmos!

In All the Old Familiar Places

The Owl in the Veil (click to embiggen). By Paul Mortfield and Stefano Cancelli

Like the Veil Nebula.  A pair of highly cool amateur astronomers named Paul Mortfield, of Backyard Astronomer fame, and Stefan Cancelli of Astro Garage made this image from observations of the Veil Nebula. It was featured on Astronomy Picture of the Day on November 1.

I don’t know about you, but I see a huge flying owl in the expanding cloud of dust and debris that marks the spot where a supernova exploded somewhere between five and eight thousand years ago.

They took their image from their observatories in the Sierra Nevadas of California, using specialty filters and no doubt some image processing to sharpen the view. Red indicates hydrogen gas, blue is oxygen and green is a combination of the two. The whole thing makes for an incredibly beautiful image.

I encourage you to check out these guys and their work at the links above. Amateurs are (as I have always felt) making incredibly good contributions to our appreciation and study of the universe.

Brilliant Massive Stars

The image below is just breathtaking.  I found it at the Astronomy Picture of the Day site and just gaped at it for a few moments. Pictures like this are what draws us all to astronomy — if for nothing else than the sheer loveliness of such distant, alien visions. This was actually released a couple of years ago as a part of a story about looking for what we thought might have been the heaviest (most massive) star in the Milky Way Galaxy. When astronomers first studied this region, they speculated that there was a single star here that could be as much as 200 solar masses, which would make it the most massive known.

It turns out that what they thought was a single massive star was, in fact, three stars with about 100 solar masses divided between them. If you’re interested, they’re the central bright stars above the cloud in this image. Even three stars having a hundred solar masses is … well… massive.  These stars will become insanely bright and stupendous supernovae when they die. And, below them is a huge stellar nursery, cranking out more hot, young stars for future astronomers to study!

Massive stars in the open cluster Pismis 24

More Cool Planetary Science

A wide-angle camera view of Mercury

Yesterday the MESSENGER mission did a close flyby of Mercury and began returning high-resolution images.  I’ll start with the last one first — it was was taken about 90 minutes after the spacecraft’s closest approach to the planet, while Messenger was on the way “out”.

The bright crater in the center is called “Kuiper” — named after Gerard Kuiper, a well-known planetary scientist.  This crater was first spotted in Mariner 10 images in the 1970s, but the real news is that this image shows terrain we haven’t seen before. Everything east of Kuiper (toward the limb (right edge) is new to our eyes. Notice the rays extending out across the whole right side of the image, emanating from a relatively fresh crater that had only been seen at low resolution from Earth using radar scanning techniques. This gives planetary scientists a whole new side of Mercury to interpret as they work to understand Mercury’s formation and cratering history.

A close-up of Mercury a few minutes after close approach.

Only a few minutes after closest approach, the spacecraft snapped this image of Mercury’s cratered, pitted surface. The last time anybody saw an image of this part of Mercury was from Mariner 10 in the 1970s. The largest impact feature at the top of the image is about 133 kilometers (83 miles) across and is named Polygnotus (who was a Greek painter who lived in the 5^th century B.C.). It has a central peak ring and is surrounded by smooth plains material (which probably was molten rock that flowed and hardened after the impact). Another large crater at the top left of the image is called Boethius (after a 6^th century Roman philosopher).  It also appears to be almost filled with smooth plains (probably formed the same way).  Sometime well after the impact which created the crater, the whole area was deformed during the formation of a prominent scarp (a cliff).

Never-before-seen terrain on Mercury

Finally, from a time about 58 minutes before closest approach, Messenger snapped this dynamic image, which I think gives a nifty 3D “feel” for those of us watching on flat screens. The features in the foreground, near the right side of the image, are close to the terminator, the line between the sunlit dayside and dark night side of the planet, so shadows are long and prominent.  You can make out two very long scarps that appear to cut across each other. One occurred first, and then sometime later, tectonic forces created the other one. The easternmost scarp also cuts through a crater, which means that it formed after the impact that created the crater. Other neighboring impact craters, such as in the upper left of this image, appear to be filled with smooth plains material (again, probably from molten rock that flowed after the impact and then cooled and hardened).

There will undoubtedly be more images coming from the MESSENGER mission. If you want to follow the action and get larger versions of all the images, point your browser to the MESSENGER website gallery. Mission scientists are examining images and putting them up as they do — so check frequently!