Category Archives: UKIRT

A Seething Hotbed of Star Birth

Another Peek at the Orion Nebula

It’s getting to be the time of year when the Orion Nebula isn’t readily available in the night sky because — well, it’s just not a sky sight for the next few months.  So, those of us who love to explore the nebula have to “make do” with the latest in professional studies of this busy, busy star birth region.

The Orion Molecular Cloud as seen by UKIRT and Spitzer Space Telescope. (Click to emiggen -- and you WANT to!)
The Orion Molecular Cloud as seen by UKIRT and Spitzer Space Telescope. (Click to embiggen -- and you WANT to!)

The kind folks at the United Kingdom Infrared Telescope (UKIRT), the IRAM Millimeter-wave Telescope in Spain,  and the orbiting Spitzer Space Telescope did a set of observations and combined them to create this stunning infrared image of the Orion Molecular Cloud. There’s a lot going on here —  star birth is NOT a serene event (just as human births aren’t exactly quiet, respectful events).

Let’s deconstruct this image. (You might want to right-click on it and open it in a new browser window to see all the details.)  First, the glowing green areas are clouds of gas and dust that are the seed material for stars. They’re usually made up of hydrogen gas and dust particles.  There are newborn stars in here — they glow in a sort of golden orange color and they’re heating up the cloud with their ultraviolet radiation. This causes the cloud to glow in a variety of wavelengths — some of them invisible to us — like infrared, which is what UKIRT, IRAM, and Spitzer are sensitive to.

So, it stands to reason that if you want to study the intricacies of star birth, you want to study the infrared light streaming from stellar nurseries.  It can cut right through most of the gas and dust in the region and give us a peek behind the clouds that often hide starbirth from us.

Newborn stars give off more than light and heat. They also emit jets during part of their infancy and childhood. Those jets shove their way out through the clouds and help sculpt the nebula.  In this image, the jets show up as tiny pink–purple arcs and dots.

A close-up of jets in the Orion Molecular Cloud (UKIRT WFCAM). (Click to embiggen.)
A close-up of jets in the Orion Molecular Cloud (UKIRT WFCAM). (Click to embiggen.)

To see the real action in this region, the astronomers took a close-up view of a jet streaming from a newborn star in one of the busier areas of star formation in this nebula.  The image was created from data acquired by the Wide Field Camera (WFCAM) at the United Kingdom Infrared Telescope.

The jet is in red, and you can see other objects — wisps, knots and filaments — that are also jets from other young stars. .

What I find cool about studying regions like the OMC is that at the same time they give us a look at star formation in the current age of the universe, they also give us a look back at the birth pangs of our own Sun and solar system some 4.5 billion years ago.  Some of the baby stars you see popping out here will someday BE like the Sun — and maybe even have their own planets.

It’s Galaxies all the Way Out

Not Turtles

There’s a story out there, written about by astronomer Stephen Hawking, but well-known to astronomers from several sources about one person’s rather interesting view of cosmology. It goes as follows.

A well-known scientist (some say it was Bertrand Russell) once gave a public lecture on astronomy. He described how the earth orbits around the sun and how the sun, in turn, orbits around the center of a vast collection of stars called our galaxy. At the end of the lecture, a little old lady at the back of the room got up and said: “What you have told us is rubbish. The world is really a flat plate supported on the back of a giant tortoise.” The scientist gave a superior smile before replying, “What is the tortoise standing on?” “You’re very clever, young man, very clever,” said the old lady. “But it’s turtles all the way down!” (taken from Wikipedia).

While space really isn’t turtles all the way down, it is more like galaxies all the way out, just about (but not quite) as far as we can see. This isn’t a surprise now that astronomers can see literally almost to the “edge” of creation (and there isn’t an edge in space, so I’m speaking poetically here). But, up until the advent of long, deep surveys of space (where astronomers spend gobs of time training specially instrumented telescopes at the sky to see farther and fainter), astronomers weren’t quite sure what they would find at great distances.

As it turns out, they find star formation beginning a few hundred galaxies and galaxy formation that seems to have started in earnest only a few hundred million years after the Big Bang. That’s pretty much in the infancy of the universe, which is about 13.7 billion years old.

So, what do these early galaxies look like? In some images, they look like little shreds of light, not yet fully formed into the distinctive spiral and elliptical shapes we are more familiar with in recent cosmic history. As time goes by, they coalesce into more detailed structures.

Astronomers in the United Kingdom have been using an infrared telescope on Mauna Kea, Hawai’i to look back into time and study galaxies as they appeared about 2.5 billion years ago. They looked at an area of the sky about the size of the full Moon and produced an image of more than 100,000 galaxies. The image below shows their cosmic zoom. The bluish galaxies in the foreground are relatively nearby; what you want to pay attention to are the little reddish dots in the background. THOSE are the very distant galaxies they are studying. So, this image is, as Dr. Sebastiaen Foucaud of University of Nottingham said today, giving astronomers a chance to do a little time travel. “I would compare these observations to the ice cores drilled deep into the Antarctic,” said Dr Foucaud. “Just as they allow us to peer back in time, our ultra-deep image allows us to look back and observe galaxies evolving at different stages in cosmic history, all the way back to just 1 billion years after the Big Bang”.

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Sebastien and others are using images like this to understand when the rarest, most massive galaxies form during the early history of the universe. This is a question that they are only now even starting to be able to answer. “We see galaxies 10 times the mass of the Milky Way already in place at very early epochs. Now, for the first time, we are sampling a large enough volume of the distant universe to be able to see them in sufficient numbers and really pin down when they were formed.”

The thing to remember here is that this cosmic “ice core” samples only one spot in the cosmos. Since galaxies are pretty much spread out in all directions (“isotropically” as the scientists say), you could take similar cores in any direction of the sky and see a backdrop of galaxies. So, while it may not be turtles all the way out, it clearly is galaxies stretching out across the universe to its infancy. Before that? The Big Bang and the Dark Ages, two other epochs of cosmic history that astronomers and cosmologists are studying as well.

Here’s more to read about this new result.