The Hubble telescope has taken some distant pictures of star formation. My very basic explanation is below. Follow the link for Alan Boyle’s description of the science behind this new image.

Just as each of us is in the centre of our own personal observable universe, so our earth is in the centre of astronomy’s observable universe. Light travels 186,000 miles per second. The light from our home star, the sun, takes about 9.3 minutes to reach us. The light reflected from planets takes several hours. The light from Alpha Centauri, the next nearest star, takes 4.2 years. So, when we look at distant galaxies, we are effectively looking back in time, at younger and younger objects. Thus, powerful telescopes enable us to see developments of stars and galaxies at different times in the past. Galaxy M83 is 15 million light-years away, so we are seeing it as it was 15 million years ago; and we can’t see it any older.

If we look far enough, we can see first-generation stars. The big bang, a sudden expansion of space-time, produced almost entirely hydrogen and helium, the two lightest atoms. Stars burn by fusion, joining nuclei to release energy and creating heavier atoms. They can continue until they get to iron, which has the lowest-energy nucleus. Creating heavier atoms would use up energy. After it creates iron, a sun’s nuclear fires burn down. Without the energy of fusion to keep it hot, the star collapses inwards because of its own gravity. The energy from gravity smashes iron atoms together and creates heavier atoms.

That’s how we know our sun is a second-generation star: our solar system contains heavier atoms than iron. The atoms in our body have already been through one star’s furnace.

Astronauts from the space shuttle Discovery started their space walk at 18:12 Eastern time. You can see it on Nasa TV.

The U.S. space shuttle Endeavor launched Wednesday night when thunderstorms stayed away. Unfortunately, it released a cloud of foam insulation on launching that might have damaged the shuttle’s ceramic insulation tiles.  The New York Times describes it thus:

Astronauts in space and engineers on the ground will spend the next few days examining and analyzing the damage to see if it might pose a danger to the shuttle on re-entry.

The shuttle Columbia disintegrated in 2003, killing the seven astronauts on board, because of damage to its wing caused by falling foam during liftoff.

Of course, that last statement is not strictly true. The Columbia was destroyed because nothing was done to assess and correct the damage before re-entry. It was just another episode of NASA’s de facto policy of “Bolt it all together and pray.” So it gave me a little chill to hear that NASA didn’t think that the lightweight foam did any damage. Did that mean they weren’t going to check it? Hadn’t they heard of velocity? Fortunately, they will still inspect the shuttle for damage.

The  U.S. space shuttle Endeavor is about to launch after several days of delays and six holds or re-schedules.

A Galaxy Zoo volunteer, Hanny Arkel, noticed an unusual object and flagged it for attention. It’s now called Hanny’s Voorwerp (Dutch for “object”).

The voorwerp is the blue blob just below the big galaxy. We’ve now decided that it’s more green than blue, so in other illustrations you’ll see it as green.

See also “Hanny’s Voorwerp revealed?“