Thursday, July 28, 2011

NASA's Chandra Observatory Images Gas Flowing Toward Black Hole

The flow of hot gas toward a black hole has been clearly imaged for the first time in X-rays.

The black hole is at the center of a large galaxy known as NGC 3115, which is located about 32 million light years from Earth. A large amount of previous data has shown material falling toward and onto black holes, but none with this clear a signature of hot gas.

By imaging the hot gas at different distances from this supermassive black hole, astronomers have observed a critical threshold where the motion of gas first becomes dominated by the black hole's gravity and falls inward. This distance from the black hole is known as the “Bondi radius.”

Trojan asteroid discovered in Earth orbit

by Stuart Gary at ABC Science.

“WISE looked at the infrared light coming from all over the sky and was particularly good at detecting asteroids, finding about 150,000 of them, including 500 which come near the Earth.”

By examining the orbits of these objects in the WISE data, Connors and colleagues identified a small asteroid called 2010 TK7 as a probable Earth Trojan. The researchers then used ground-based telescopes to confirm the sighting, calculating that it's been in a stable orbit with Earth for more than 10,000 years.

Image credit: NASA/JPL-Caltech

Living On the Web With Chromebook

Good for Battery Life by Louis Gray.

3D printing: The world's first printed plane

by Paul Marks at New Scientist.

How Facebook Moved 30 GB of Hadoop Data

Post by @DerrickHarris at @Gigaom.

Monday, July 25, 2011

Byte is Back

Byte magazine is back at, under the new editorship of Gina Smith.  And it even features the return of Jerry Pournelle and his Chaos Manor column!

She reposted the original editor, Carl Helmers', introductory letter.

I first discovered Byte when I bought my first issue at the Georgia Tech Bookstore.  I'm pretty sure it was volume one but I'm not clear on which issue it was.  I think I still have it around here somewhere.  I need to dig it out and check.  I thought it was issue #2, but looking up issues online, I'm now in doubt.

TWIT Moves to the New Studio

[VIDEO] Leo Laporte shuts down the old cottage and walks down the street to the new brick house studio.  Jason Cartwright posts about the move on TechAU.

Thursday, July 07, 2011

Instantwatcher for Netflix

For keeping with with movies coming and going on Netflix, Instantwatcher is quite good.

Tuesday, July 05, 2011

Dark Energy and Zombie Stars

by Tammy Plotner from Universe Today.

Image credit: Supernova 1994D. The supernova is the bright point in the lower-left. It is a type Ia thermonuclear supernova like those described by Howell. The supernova is on the edge of galaxy NGC 4526, depicted in the center of the image. Credit: NASA/Hubble Space Telescope

Monday, July 04, 2011

The Outer Limits Influence on Star Trek

I must have read it before but I didn't realize or remember the ties from The Outer Limits to Star Trek.

Sunday, July 03, 2011

Google Fixes Privacy Flaw? (Part 2)

Okay, when you write a post (or even after) there's a little drop down menu (triangle, arrow thing) at it's upper right.  One of the options is to disallow re-sharing.  You have to do it manually every time I think—I don't see a way to make that the default setting.

That's better than not having that option at all, better than email, and also annoying to have to do.

(Part 1)

Google+ Solves the Social Privacy Problem

By Making Friending Very Complicated by @LizGannes at All Things D.

Saturday, July 02, 2011

Google Fixes Privacy Flaw?

(SAI Business Insider)  Oh no.  I thought G+ didn't allow a reader to reshare a post to a wider audience than the original post.

Google+ and Twitter

So I just reposted a story about the halo seen in Hawaii.  I found that story by reading my sparks (spark?) on Google+ where I've entered astronomy as an interest.  The question is, would I have seen it reading my Twitter feed?

I scanned back through my main Twitter stream for about an hour, which is a typical short reading session for me.  A long session might involve reading back through two or three hours.

Then I went to my astronomy Twitter list and read back through those messages, well into yesterday.

The story wasn't there, or at least I didn't catch it.  (Granted I did a quick skim and didn't actually read the Twitter posts).  Hm.

Weird Expanding Halo Seen from Hawaii

Explained by the Bad Astronomer.

Another idea posted by board member neufer was that this was from a detonation charge in the missile’s third stage. There are ports, openings in the sides of the third stage. Those ports are sealed for the flight until the right time, when they’re blown open by explosive charges. This allows the fuel to escape very rapidly, extinguishing the thrust at a precise time to allow for accurate targeting of the warhead.

At this point, the missile is above most of the Earth’s atmosphere, essentially in space. So when that gas is suddenly released from the stage expands, it blows away from the missile in a sphere. Not only that, the release is so rapid it would expand like a spherical shell — which would look like a ring from the ground (the same way a soap bubble looks like a ring). And not only that, but the expanding gas would be moving very rapidly relative to the ground since the missile would’ve been moving rapidly at this point in the flight.
Image credit:  Frame processed by Phil Plait from the video by Kanoa Withington/CFHT.