RSS

Tag telescope

Planetary Mashup

0 comments By Kate Filed in astronomy, science Tagged with , , , , August 10th, 2009 @ 12:02 pm

Using the Spitzer Space Telescope, astronomers have found a planetary collision 100 light-years away, near a star that goes by the name of HD 172555. Evidently, an object the size of the Moon smashed into one the size of Mercury. NASA has an awesome animation of the event below:



According to the Bad Astronomy Blog at Discover.com, astronomers found the collision when they were looking at spectra from HD 172555. In addition to hydrogen, helium, and the other usual suspects, the spectra showed evidence of an unusually large amount of amorphous silica, as in glass. From blogger/astronomer Phil Plait:

Glass? From a star?
The most likely explanation is that the glass is in the form of tektites, which are blobs of glassy material that form when something big hits something else big. The silica gets fused into glass. But that means that there was a pretty big impact that must have happened at that star, and that in turn means that two planet-sized objects must have had a very bad day. This was supported by the detection of other chemicals consistent with the aftermath of a massive collision.
The best fit to the data suggest that one object was planet-sized and the other Moon-sized, meaning the collision would have been at very high speed — several kilometers per second — and launched an unimaginable amount of material into space. Furthermore, it couldn’t have happened too long ago, or else the material would have dissipated and wouldn’t have been seen. It looks like this was a recent event, then, occurring maybe only a few thousand years ago!

I should note that while the animation is impressive, it’s somewhat misleading. Plait explains:

P.S. The animation above is cool, but not a perfect representation of what happened. For example, the shock wave ring travels around the planet as shown, but when the ring converges on the point opposite the collision point, there would be a huge explosion and a vast plume of material launched into space. No one ever puts that in their animations, and I think it would be very cool! I need to get people who create physics-based simulations to make one that’s accurate, so it can be used in situations like this.

One Big Telescope

1 comment By Kate Filed in astronomy, science Tagged with , , , , , , July 28th, 2009 @ 11:03 pm

I had the opportunity to visit Lick Observatory a few weekends ago. Jill and I took the windy road up Mt. Hamilton, just east of San Jose to attend an event called Music of the Spheres, which included a music concert, an astronomy lecture, and some telescope-peeping.

For the most part the event was awesome. I must admit that the music of Tingstad and Rumbell (who I keep referring to as Tungsten and Ribald) was somewhat dull to my unaccustomed ear, but the lecture more than made up for it. Deborah Fischer of SFSU was supposed to talk about the search for exoplanets, but her flight was delayed and she couldn’t make it. Instead, a Lick Observatory regular gave a delightful and entertaining talk about the history of the facility. I was ready to be bored, but the story of the wealthy, eccentric James Lick and all the cool research at the observatory, like adaptive optics that take the twinkle out of stars, was really amazing.

The main attraction at the event should have been the massive 36-inch refractive telescope, built in 1888 and still the second largest in the world. They just don’t make them like this anymore because it’s far too expensive and nearly physically impossible to build lenses much larger. And more importantly, it’s unnecessary to make a refractive telescope this large because most optical telescopes are reflective, and use curved mirrors to focus light instead of lenses. Unfortunately for us, though, the night was cloudy and there was moisture in the air, which meant that the dome that encloses the telescope couldn’t be opened because water degrades the lens. Still, anyone who wanted it was able to snag some star-gazing time. Amateurs who built their own scopes set up in the parking lot and pointed toward globular clusters, nebulae, and a nearly full moon as the clouds permitted.

When the engineers designed this 36-inch refractive telescope, they made it about a foot too long. So on the night that it was supposed to see light for the first time, astronomers took a hacksaw to the back end and held up the eyepiece until the stars were in focus.

When the engineers designed this 36-inch refractive telescope, they made it about a foot too long. So on the night that it was supposed to see light for the first time, astronomers took a hacksaw to the back end and held up the eyepiece until the stars were in focus.

This is the other end of the telescope. Unforutnately, the lens cap had to stay on during our visit because there was moisture in the air.

This is the other end of the telescope. Unforutnately, the lens cap had to stay on during our visit because there was moisture in the air.

This shot, in particular, shows off the steampunk-y nature of the observatory.

This shot, in particular, shows off the steampunk-y nature of the observatory.

Copyright © kategreene.net
Science and Technology and Other Stuff

Built on Notes Blog Core
Powered by WordPress