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hubble space telescope, musings

The Passage of Time

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Hubble Space Telescope

A model of the Hubble Space Telescope at the National Air and Space Museum in Washington, D.C. Click to enlarge.

I had a chance to go to the National Air and Space Museum for the AAS banquet last night. Before dinner, we had a chance to wander around and look at the exhibits in the museum.

As usual, I gravitated to the Hubble Space Telescope model and the exhibit that features its back-up mirror and a special presentation of the Wide Field Planetary Camera 2 that is on temporary loan to the museum. I had a nice long time to stand there and contemplate the telescope that was a large part of my graduate school experience — and, of course, my writing experience.  Back in graduate school I worked as one member of a large team that supported and used one of the original instruments on the telescope — the Goddard High Resolution Spectrograph. This instrument used the telescope to study objects in the universe in ultraviolet light. It was eventually removed from the telescope, but while it was deployed, GHRS turned out some seminal science.

When I decided to write Hubble Vision (my first major science book, with co-author Jack Brandt) and also the planetarium show that is showing in facilities around the world, it was clear to me that I needed to show people that astronomy is a multi-wavelength endeavor — and that most people don’t know that fact.  And, given the gorgeousity of HST’s optical images (and those from optical telescopes on the ground), that’s completely understandable.

These days, we are rather more used to seeing imagery created from observations in all wavelengths. People are more used to such visions, and that idea stimulated the book Visions of the Cosmos (that Jack and I also co-authored).  We enjoyed bringing a new vision of the universe to readers, and I think the days of knowing the cosmos only through the wavelengths our eyeballs can see are coming to an end.

Well, all these thoughts ran through my mind as I stood looking at the HST model last night. That telescope set me on a path that I could never have foreseen — an interesting and twisty path, but an ultimately rewarding one. Those thoughts — and memories of the early days of HST, the problems, the triumphs, the team meetings, the work we did — all seemed, paradoxically fresh — and old — at the same time.   One of these days, I’ll go to NASM and maybe our instrument will be an exhibit. I’ll feel really old, but it will also be a testament to the work that thousands of people did for many years to bring another vision of the cosmos to our senses.

30 doradus, hubble space telescope, starbirth

More Starbirth Than You Can Shake a Telescope At

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Hubble Peers Into a Stellar Nursery

R136 in the Large Magellanic Cloud, courtesy of Hubble Space Telescope. Click to embiggen.
R136 in the Large Magellanic Cloud, courtesy of Hubble Space Telescope. Click to embiggen.

Every time I turn around, Hubble Space Telescope is looking at another fantastic place in the cosmos. This time, it’s a massive region of starbirth, where gigantic hot young newborn stars are crowded together in an area where there are even MORE stars are still being  created.

The scene that Hubble imaged is 30 Doradus, a starbirth nursery that’s wracked with the turbulent winds and activity that accompany the births of stars in close quarters.  The hot blue stars you see in this image are part of a cluster called R136. They are but a few million years old and lie about 170,000 light-years away in the neighboring Large Magellanic Cloud (a companion galaxy to the Milky Way).

Many of these icy blue stars are among the most massive stars known. Several of them are over 100 times more massive than our Sun.  They may look pretty now, but in a few million years, they will have spent their nuclear fuel and will start to pop off like firecrackers in giant supernova explosions.

The clouds surrounding these stars are being carved away by relentless and prodigious amounts of ultraviolet radiation and stellar winds pouring off the hot young stellar beauties.  That action is etching away at the enveloping hydrogen gas cloud in which the stars were born — and, in the process, in some places it may well be choking off the materials that other stars that need to form in the future.

Now, the stellar winds and radiation aren’t the only action going on here. The motion of the Large Magellanic Cloud itself may have played a huge role in starting the whole star-birth process in 30 Doradus.  First, the gravitational tug of the Milky Way and the companion Small Magellanic Cloud may have acted together to push the gas clouds in the LMC together.  You need highly compressed clouds of gas and dust to start the stellar nursery chugging away cranking out new stars.

It’s also likely that when the Large Magellanic Cloud plowed through the halo of the Milky Way in the distant past, that action could also have compressed clouds of gas and dust, setting the stage for star formation. As fascinating as this is because it’s happening relatively near to our galaxy, this same scene has played itself out many times through out the early history of the universe. In distant regions where galaxies have collided, massive clusters like R136 are common and this tells us that glaaxy interactions are a great spur to star birth.  This image is a great example of studying something close to us that gives us great insight into something that happened in galaxies long ago and far, far away.