Know What’s Happening Here?

M82
M82

Neither did I, some 25 years ago when I first wrote about M82 in a planetarium show. At the time nobody was quite sure what was happening at the center of this galaxy. It looked like it could be blowing itself apart; a stellar city disrupted by tremendous forces. Well, times have changed. We have better telescopes, stronger “glasses” if you will, and now we can look into the heart of M82 and see that it’s really harboring a galactic construction site, a humongous starbirth nursery that’s blowing winds across space. To be sure there’s a little stardeath going on here, too. Supernovae—the deaths of massive stars—are also blowing strong winds across space, fueling the frenetic appearance of the scene. Here’s what the Astronomy Picture of the Day site says about this image:

“Star formation occurs at a faster pace in M82—a galaxy with about ten times the rate of massive star birth (and death) compared to our Milky Way. Winds from massive stars and blasts from supernova explosions have created a billowing cloud of expanding gas from this remarkable starburst galaxy. The above scientifically color-coded image highlights the complexity and origin of the plume by combining a wide field image from the WIYN Telescope in Arizona with a smaller high-resolution image from the orbiting Hubble Space Telescope. M82’s aspect in optical pictures has led to its popular moniker, the Cigar Galaxy. M82’s burst of star formation was likely triggered a mere 100 million years ago in the latest of a series of bouts with neighboring large galaxy M81.

This is what keeps me fascinated about astronomy. The better our tools become, the more we learn, and of course, the more questions we ask about the cosmos. I wonder what future telescopes will see at the heart of M82?

Calling All Pleiadeans

Courtesy Space Telescope Science Institute.
Courtesy Space Telescope Science Institute.

The Pleiades—that little cluster of stars that makes wintertime stargazing so nice (among so many other other night-time delights) came in for some extra interest by Hubble Space Telescope recently. Astronomers wanted to determine the distance to this little grouping. It’s not always been easy to tell how far away they are, and in fact their distance has been the subject of controversy among astronomers.

Measurements made by the Hipparcos satellite suggested that they were closer to Earth than observers used to think. However, other astronomers measured the distance and found it to be farther out. HST’s studies found the same result: the Pleiades lie about 440 light-years away from us. The image above shows the Pleiades with Hubble’s field of view superimposed over parts of the cluster.

Why all the fuss? Because if those stars lay farther away (as Hipparcos suggested) their brightness wouldn’t match with what we know about star characteristics (particularly sun-like stars).

It may seem like a tweak in distance measurements, but it’s an important one if we are to understand how stars form and how they live. Astronomy is often like that— giving us tantalizing hints about the nature of objects and leaving it up to us to measure and chart the details.

So, if you’re a Pleiadean (one interested in this glittery little set of stars, not necessarily someone who thinks you’re from the Pleiades), take heart: from 440 light-years away, they’re helping us understand more about stars like our Sun.