An earlier version of this panoramic image was an Astronomy Picture Of The Day in 2001, but the Panorama 2.0 is much, much more detailed, and Mellinger has eliminated some distortions and other problems in the original image.

According to a press release from the University of Chicago Press:

Piecing together 3000 individual photographs, a physicist has made a new high-resolution panoramic image of the full night sky, with the Milky Way galaxy as its centerpiece. Axel Mellinger, a professor at Central Michigan University, describes the process of making the panorama in the forthcoming issue of Publications of the Astronomical Society of the Pacific. An interactive version of the picture can viewed on Mellinger's website.

"This panorama image shows stars 1000 times fainter than the human eye can see, as well as hundreds of galaxies, star clusters and nebulae," Mellinger said. Its high resolution makes the panorama useful for both educational and scientific purposes, he says.

Mellinger spent 22 months and traveled over 26,000 miles to take digital photographs at dark sky locations in South Africa, Texas and Michigan. After the photographs were taken, "the real work started," Mellinger said.

Simply cutting and pasting the images together into one big picture would not work. Each photograph is a two-dimensional projection of the celestial sphere. As such, each one contains distortions, in much the same way that flat maps of the round Earth are distorted. In order for the images to fit together seamlessly, those distortions had to be accounted for. To do that, Mellinger used a mathematical model-and hundreds of hours in front of a computer.

Another problem Mellinger had to deal with was the differing background light in each photograph.

"Due to artificial light pollution, natural air glow, as well as sunlight scattered by dust in our solar system, it is virtually impossible to take a wide-field astronomical photograph that has a perfectly uniform background," Mellinger said.

To fix this, Mellinger used data from the Pioneer 10 and 11 space probes. The data allowed him to distinguish star light from unwanted background light. He could then edit out the varying background light in each photograph. That way they would fit together without looking patchy.

The result is an image of our home galaxy that no star-gazer could ever see from a single spot on earth. Mellinger plans to make the giant 648 megapixel image available to planetariums around the world.

[University of Chicago via Axel Mellinger via Examiner]

Bad Astronomy]

The diffuse X-ray light suffusing the image comes from gas that has been heated by stellar explosions, massive young stars — and outflows powered by the supermassive blackhole at the heart of the galaxy, Sagittarius A. Scientists believe Sagittarius A gave off giant X-ray flares 50 years and 300 years earlier. (So when we finally visit the center of the galaxy searching for the mythical planet Sha-Ka-Ree in order to meet God and ask him why he wants a spaceship, we should time our visit to avoid one of those irregular X-ray bursts.) [Chandra]

Most geologists believe that Devil's Tower in the Black Hills of Wyoming was formed by a hardened plume of lava that never broke through to the surface. Unlike most national monuments, visitors are allowed to climb Devil's Tower and get an extraordinary view of the night sky. In this view of the Milky Way, we can see strands of the Pipe Nebula:

As well as the red glow of the Lagoon Nebula to the right of the Tower:

[Astronomy Picture of the Day]

The data fits with the extinction of the dinosaurs 65 million years ago and another extinction at the end of the Paleocene period, 35 million years ago. It also means our planet's probably in for another life-ending black eye in the not too-distant future.

But what's Galactic density got to do with comet impacts? As the solar system moves through denser parts of the galaxy the extra gravitational pull upsets comets orbiting the Sun, sending them hurtling towards Earth. The theory's been tossed around for a while (and there are other good ones, like supervolcanoes, that haven't been discounted yet) but this new evidence makes it seems a little more believable.

It sucks to think that gravity — a pretty immutable force of nature — will be the source of our demise rather than something we can avoid, like global warming or nuclear war. But the study suggests there may be a silver lining to our extinction: comet impacts could be the driving force behind panspermia:

While the "bounce" effect may have been bad news for dinosaurs, it may also have helped life to spread. The scientists suggest the impact may have thrown debris containing micro-organisms out into space and across the universe.

Centre director Professor Chandra Wickramasinghe said: "This is a seminal paper which places the comet-life interaction on a firm basis, and shows a mechanism by which life can be dispersed on a galactic scale."

Source: Cardiff University via Science Blog

Image: The Alien Next Door