WISE: NASA’s Eye In The Infrared

This week NASA released this stunningly beautiful infrared image of the Pleiades passing through a cloud of dust.

The image was taken by WISE, the acronym for NASA’s Wide-field WISE_artist_concept_(PIA17254,_crop)Infrared Survey Explorer. WISE was launched in December of 2009. By early 2011 WISE had completed its initial mission of infrared mapping of the entire sky twice.

 

NASA lists the accomplishments of WISE’s initial mission as:

– Contributing to evidence ruling out the existence of Planet X in the Kuiper Belt

– Discovery of millions of previously unknown black holes

– Discovery of the coolest (think temperature) class of stars

– Provided data used to image what is the most luminous galaxy yet found in the galaxy.

NASA states that data gathered by WISE has been used to publish over 1,000 scientific studies.

Upon completion of its mapping task in 2011, WISE was put into hibernation.

In September of 2013 WISE was reactivated and given another mission, NEOWISE, NEO standing for Near Earth Objects. In this role WISE has made several important discoveries:

– Making the most accurate statistical estimate to date of asteroids which pose a threat to the Earth

– Establishing that 93% of near earth asteroids greater than one half mile wide had already been found by NASA, and that the overall population of such asteroids was slightly smaller than previously thought

– Tracked asteroids with unusual elliptical orbits back to the Euphrosyne group, asteroids above the general asteroid plane in the solar system

– Discovered Earth’s first known Trojan, that is, an asteroid tracking the Earth’s orbit around the Sun.

NASA describes the instrument WISE uses to gather data:

“The WISE telescope has a 40-centimeter-diameter (16-inch) aperture and is designed to continuously image broad swaths of sky at four infrared wavelengths as the satellite wheels around Earth. The four wavelength bands are 3.4, 4.6, 12 and 22 microns. The field of view is 47-arcminutes wide, or about one-and-a-half times the diameter of the moon.

The telescope was built by L-3 SSG-Tinsley in Wilmington, Mass. Its design uses a total of 10 curved and two flat mirrors, all made of aluminum and coated in gold to improve their ability to reflect infrared light. Four of the mirrors form an image from the 40-centimeter primary mirror onto the flat scan mirror.”

Once the data is gathered analysis begins:

“Light gathered by WISE’s telescope is focused onto what is called a focal plane, which consists of four detector arrays, one for each infrared wavelength observed by WISE. Each of the detector arrays contain about one million pixels (1,032,256 to be exact). This is a giant technology leap over past infrared survey missions. The Infrared Astronomical Satellite’s detectors contained only 62 pixels in total.”

WISE has given us great leaps forward in our knowledge of both the infrared activity in the near and distant sky as well as the activity of near earth objects.

“Great leaps forward” in any field usually mean that you didn’t know all that much to begin with and that you probably still have a lot to learn.

The image is in some ways eerie. The stars of the Pleiades cluster are passing through a cloud of dust, an accidental meeting in the cosmos. It is a moment in time, granted a two hundred million year moment, but a moment nevertheless.

How small are we in the scheme of things? How much more do we have to learn? How wonderful, daunting, super-human and exhilarating is the challenge to make a future for mankind.

 

 

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