Futurehead.com

Wednesday, 25 November 2009 11:18

A new three-dimensional map of the Milky Way should give astronomers a unique insight into the formation and evolution of our galaxy.

Mapping the galaxy is tricky business because of the inherent difficulties in measuring distances to stars. The problem boils down to determining the inherent brightness of a star, a property called its absolute magnitude. Then the difference between this and its observed magnitude on Earth gives you some idea of its distance.

But how to determine absolute magnitude? One way is to use the famous Hertzprung-Russel diagram (also known as the colour magnitude diagram), which plots the relationship between a star's colour and its absolute magnitude. The process is relatively straightforward: measure a star's colour and observed magnitude, then determine its absolute magnitude from the colour magnitude diagram. A straightforward calculation should give you its distance (provided there's no dust obscuring your view).

Read full article

Main Menu

The Futurehead poll

Is our modern diet killing us, and if so, why?

	Yes, too much fat
	Yes, too much carbohydrate
	No, we just don't excercise enough
	It's more complicated than any of the above

NASA Image Of The Day


Orbital Sunrise
The Expedition 24 crew on the International Space Station photographed this image of polar mesospheric clouds illuminated by an orbital sunrise. Polar mesospheric, or noctilucent ("night shining"), clouds usually are seen at twilight, following the setting of the sun below the horizon and darkening of Earth's surface. Occasionally the station's orbital track becomes nearly parallel to Earth's day/night terminator for a time, allowing the clouds to be visible to the crew at times other than the usual twilight because of the station's altitude. This photograph shows polar mesospheric clouds illuminated by the rising, rather than setting, sun at center right. Low clouds on the horizon appear yellow and orange, while higher clouds and aerosols are illuminated a brilliant white. Polar mesospheric clouds appear as light blue ribbons extending across the top of the image. The station was located over the Greek island of Kos in the Aegean Sea (near the southwestern coastline of Turkey) when the image was taken at approximately midnight local time. The orbital complex was tracking northeastward, nearly parallel to the terminator, making it possible to observe an apparent "sunrise" located almost due north. A similar unusual alignment of the ISS orbit track, terminator position and seasonal position of Earth's orbit around the sun allowed for this striking imagery of over the Southern Hemisphere. Image Credit: NASA...
02 Sep 2010
800x600	1024x768	Large

Subscribe to Futurehead.com

Latest

In Futuredise Store

Text Link Ads

Visitor Medical Insurance

Technology Quotes of the Day

Furthermore, we believe that health care reform, again I said at the beginning of my remarks, that we sent the three pillars that the President's economic stabilization and job creation initiatives were education and innovation - innovation begins in the classroom - clean energy and climate, addressing the climate issues in an innovative way to keep us number one and competitive in the world with the new technology, and the third, first among equals I may say, is health care, health insurance reform.

Nancy Pelosi

By iWeb Design

Brain Quotes of the Day

Art is not the application of a canon of beauty but what the instinct and the brain can conceive beyond any canon. When we love a woman we don't start measuring her limbs.

Pablo Picasso

By iWeb Design

Evolution Quotes of the Day

According to the concept of transformational evolution, first clearly articulated by Lamarck, evolution consists of the gradual transformation of organisms from one condition of existence to another.

Ernst Mayr

By iWeb Design