Gaia is two space telescopes in one.  There are ten mirrors of various sizes and shapes used to collect, focus and direct light to Gaia's instruments.  The telescopes point to two different positions in the sky separated by 106.5 degrees.  Each scope has a rectangular primary mirror with a collecting area of about 0.7 square meters.  Three flat mirrors and three curved mirrors are used to focus and fold the light beam over a total path of 35 meters.  Gaia's telescopes are powerful enough to detect stars up to 400,000 times fainter than those visible to the naked eye.

Gaia incorporates three instruments to detect the light, the astrometric instrument, the Radial Velocity Spectrometer and the photometric instrument.  The 106 CCDs that record the light from the stars create the largest focal plane ever flown in space, almost one billion pixels covering 0.38 square meters.

The star's positions are measured by the astrometric instrument.  As each star is measured 70 times during the five year mission, the data can be combined to determine an accurate distance as well as the velocity and direction the star is moving across the sky.

The Radial Velocity Spectrometer will measure the Doppler shift of the the absorption lines in a high resolution spectrum covering a narrow wavelength range.  This will tell us the velocity of the stars in the direction of moving away or toward us.

Color information is obtained by the photometric instrument.  Two low-resolution specta, one in the blue and one in the red are generated.  This will reveal the star's temperature, mass and chemical composition.

With instruments like these, measuring the stars at a never before achieved accuracy, Gaia will certainly advance the science of astronomy to new levels.  At the end of the five year mission, Gaia will have collected over 1 Petabyte (1 million Gigabytes) of data, enough to fill over 200,000 DVDs.

Galaxies are dusty places.  But where did all that dust come from?  For the first time, we have now seen the remains of a recent supernova brimming with freshly formed dust.

The Atacama Large Millimeter/submillimeter Array (ALMA) in Chile has been examining the supernova 1987A, located in the Large Magellanic Cloud.  The Large Magellanic Cloud is a dwarf galaxy located about 160,000 light-years from Earth.  For the first time in history we are able to examine a supernova with unprecedented resolution and sensitivity.

As the gas cooled after the explosion, it was predicted that large amounts of dust would form atoms of oxygen, carbon and silicon bonded together in the cold central regions of the remnant.  But as SN 1987A was observed in the infrared during the first 500 days after the explosion, only a small amount of dust was detected.

ALMA, however, is able to look at the cold dust in the millimeter and submillimeter wavelengths.  Here they have found the abundant dust they predicted.  Astronomers estimate that the remnant now contains about 25 percent the mass of the Sun in newly formed dust.  Additionally, significant amounts of carbon monoxide and silicon monoxide have formed.

Mikako Matsuura of the University College London says, "Really early galaxies are incredibly dusty and this dust plays a major role in the evolution of galaxies.  Today we know dust can be created in several ways, but in the early Universe most of it must have come from supernovae.  We finally have direct evidence to support that theory."