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Monday, December 14, 2009

WISE: NASA launches a new space telescope

A new NASA space telescope was successfully launched today from Vandenberg Air Force Base in California. This new space telescope known as WISE (which stands for Wide-field Infrared Survey Explorer),  was launched aboard a Delta II rocket.

"The satellite will orbit the Earth over the north and south poles and will detect objects that are difficult to see from the ground, including asteroids, and stars such as brown dwarfs, and galaxies that shine brightly in infrared light."

"The last time we mapped the whole sky at these particular infrared wavelengths was 26 years ago," said Edward Wright of UCLA, the principal investigator of the mission.
"Infrared technology has come a long way since then. The old all-sky infrared pictures were like impressionist paintings. Now, we'll have images that look like actual photographs," he said in a statement.
"Once in orbit, the valves in the telescope's cooling system will automatically open, venting super-cooled hydrogen into space."
An artist's concept of NASA's WISE space telescope.  
An artist's concept of NASA's WISE space telescope. (NASA/JPL)

"By venting the hydrogen to space, we cool our instrument down to extremely low temperatures so that the eyes of WISE won't be blinded by their own heat," said William Irace, the mission's project manager at NASA's Jet Propulsion Laboratory.
"Because WISE has a limited supply of hydrogen coolant, the satellite's mission will last only about 10 months, enough time to survey the entire sky about one-and-a-half times."
source: http://www.cbc.ca/technology/story/2009/12/14/tech-space-wise-telescope-launch.html



Here is some additional information about WISE:

According to the website, http://wise.ssl.berkeley.edu/mission.html,

"WISE is an unmanned satellite carrying an infrared-sensitive telescope that will image the entire sky. Since objects around room temperature emit infrared radiation, the WISE telescope and detectors are kept very cold (below -430° F /15 Kelvins, which is only 15° Centigrade above absolute zero) by a cryostat -- like an ice chest but filled with solid hydrogen instead of ice."

"Solar panels will provide WISE with the electricity it needs to operate, and will always point toward the Sun. Orbiting several hundred miles above the dividing line between night and day on Earth, the telescope will look out at right angles to the Sun and will always point away from Earth. As WISE orbits from the North pole to the equator to the South pole and then back up to the North pole, the telescope will sweep out a circle in the sky. As the Earth moves around the Sun, this circle will move around the sky, and after six months WISE will have observed the whole sky."

"As WISE sweeps along the circle a small mirror scans in the opposite direction, capturing an image of the sky onto an infrared sensitive digital camera which will take a picture every 11 seconds. Each picture will cover an area of the sky 3 times larger than the full Moon. After 6 months WISE will have taken nearly 1,500,000 pictures covering the entire sky. Each picture will have one megapixel at each of four different wavelengths that range from 5 to 35 times longer than the longest waves the human eye can see. Data taken by WISE will be downloaded by radio transmission 4 times per day to computers on the ground which will combine the many images taken by WISE into an atlas covering the entire celestial sphere and a list of all the detected objects."

"WISE will:
■ Find the most luminous galaxies in the Universe.
■ Find the closest stars to the Sun.
■ Detect most Main Belt asteroids larger than 3 km.
■ Enable a wide variety of studies ranging from
the evolution of planetary debris discs to the history
of star formation in normal galaxies."

"The WISE instrument is a four-channel imager which operates
in a single mode, taking overlapping snapshots of the
sky. It includes:
■ A 40-cm telescope and reimaging optics.
■ A scan mirror to stabilize the line-of-sight while the spacecraft
scans the sky."

Source: http://wise.ssl.berkeley.edu/sb/documents/FactSheet.2009.9.09_web.pdf

"WISE will only be going to low Earth orbit (523 km above the ground). It will be exploring the entire Universe by collecting infrared light that comes to us from everywhere in space."

"WISE will survey the whole sky in infrared light, and will produce an all-sky image atlas and catalogue of over 300 million infrared sources. Things of particular interest to the scientists working on WISE are asteroids, the coldest and nearest stars, regions of new star and planet formation, the structure of the Milky Way Galaxy, Ultra-luminous infrared galaxies, and the large scale structure of the Universe."

This mission is important to NASA for the following reasons:


"WISE will find the nearest stars (brown dwarfs), detect near-Earth asteroids, and observe Ultra-luminous infrared galaxies. WISE will fill the gap in all-sky surveys in the mid-infrared. There are several current or upcoming all-sky surveys all across the electromagnetic spectrum, but there is a gap in the infrared coverage from 3-23 microns. WISE fills that gap. WISE will create a catalog of over 300 million sources that will be of interest to future infrared studies, especially the James Webb Space Telescope"

How does this telescope work?
"The telescope works much like a digital camera. Instead of lenses to create an image it uses mirrors. It collects light with mirrors, uses mirrors, beam splitters, and filters to separate the light into four infrared wavelength bands, and then focuses the four beams onto four different detectors: two made of mercury, cadmium, telluride and two of silicon and arsenic. These four detectors form digital images which are stored on onboard computers and transmitted to the ground via radio communications."
Why are asteroids seen better in the infrared?
Asteroids generally have dark surfaces and do not reflect much visible sunlight. They do absorb the sunlight that falls on them. This heats them up and they glow in the infrared (heat).

What’s the significance of a star giving off infrared?
Any object with a temperature just above absolute zero will give off some kind of infrared. Stars are much hotter and produce plenty of infrared. Stars like the Sun put out most of their light in visible light (not a coincidence). Hotter stars put out most of their light in ultraviolet, while cooler stars put out most of their light in infrared. So infrared is especially useful in studying cool stars (a few hundred to a few thousand degrees Kelvin). They can be either giant or dwarf stars.


Will WISE look for asteroids or planets in, or forming in, other solar systems, especially Earth-like planets?
WISE cannot resolve individual objects in other star systems. But, it can see the dusty debris disks around other stars. These debris disks can be part of planetary formation and result from cometary activity. Characterizing these debris disks will help astronomers better understand the process of planet formation.

How do stars form?
Huge clouds of dust and gas can become compressed enough that their own self gravity begins to pull them together. They collapse under their own weight. Stars form in the densest regions where gravity is pulling the matter together and the compression of the material heats it up. They spin faster and faster as they get smaller (conserving angular momentum), which forms debris disks about them. Planets or even secondary stars can form in the debris disk. When the core of the star become dense and hot enough nuclear fusion ignites and the star becomes stable.

How are the galaxies (that WISE will find) different, if at all?
WISE will find a special class of galaxies that have tons of star formation occurring. Star formation is often shrouded in dust, so little visible light gets out. But the heated dust radiates all of the energy of the stars away in infrared light. These galaxies are called Ultra-luminous infrared galaxies (ULIRGs). They often appear to be the result of merging galaxies, and also often have supermassive black holes in their cores undergoing Quasar-like activity.

Are most of the sources to be studied actually stellar sources?
There will be 100,000s of asteroids detected by WISE. But there will be millions of stars and millions of galaxies seen by WISE.

How far can you see with this? Will this telescope see to the edge of the Universe?
The most luminous galaxies will be seen by WISE and they probably exist more than halfway across the Universe. There may be some quasars visible to WISE from very early in the history of the Universe and hence very far away, possibly near the edge of the cosmic horizon.


Source:http://wise.ssl.berkeley.edu/mission_faq.html

Here is a link to a large photo of the telescope carried by WISE:


http://wise.ssl.berkeley.edu/gallery_images/h5_lg.jpg

According to the website:  http://www.theatlanticwire.com/opinions/view/opinion/What-NASAs-WISE-Telescope-Might-Find-1910 

these are the key goals of the WISE mission:


As reported by Robert Block in the Orlando Sentinel, one of WISE's chief goals will be cataloging (relatively) near-earth asteroids with the hopes of avoiding a catastrophic impact in the future: "A killer space rock heading for Earth is not just the stuff of Hollywood action movies and science fiction stories. The threat is real and getting a better handle on near-Earth asteroids could ease some concerns by scientists that NASA had not been doing enough." Meanwhile, Marginal Revolution Alex Tabarrok calls the operation a critical and overlooked part of space exploration:
The example may seem fanciful but [co-blogger Tyler Cowen] and I are quite serious about the importance of asteroid deflection. Large asteroid hits are rare but if a large asteroid does hit, billions will be killed. As a result, sober calculations suggest that the risk of dying from an asteroid strike is about the same as the risk of dying in a commercial airplane crash.
  • WISE will also look for Extra Planets The Times Online's Hannah Devlin quotes an astronomer who thinks that WISE could resurrect some out-of-vogue theories: "There was a theory about 20 years ago, based on gravitational observations, that there was a giant planet called Nemesis way out beyond Pluto," said Professor Michael Barlow, a planetary scientist at University College London. The theory has fallen out of favour in recent years but any such planet could be discovered by the new telescope, he said."
  • WISE will search for Closer Stars Technology author and space-travel enthusiast Paul Gilster is most excited about WISE being what he calls a "Brown Dwarf Hunter Extraordinaire," i.e. a machine more capable of finding nearby dark stars than any before: "WISE will be able to detect stars much dimmer than the Sun. These brown dwarfs, many of which have yet to be discovered, should be readily apparent to the WISE instrument, and of course we hope for one that ranks as the closest star to the Earth. And beyond all this, WISE will be able to produce a global map of the galaxy and its associated dust."
  • WISE will try to find Black Hole Factories Joe Pappalardo of Popular Mechanics breaks WISE's mission down into three main components, one of which he says is looking for the birthplace of black holes:
When galaxies collide, they sometimes produce large numbers of stars as dust and gasses consolidate. This process produces a lot of infrared light, making these incidents high on the list of interesting things WISE will observe ... There may also be supermassive black holes at the centers of these new galaxies. "
  • Lastly, WISE will try and find Aliens Gizomodo's Adam Frucci hopes that the telescope will be able to spot something that has so far remained elusive to Earth's skywatchers: "It'll be used to detect light- and heat-emitting objects that the Hubble might miss. Such as spaceships, I'll bet!"


Here is a very interesting video I found about the WISE mission:




source http://www.youtube.com/watch?v=nhwjCwa2YlI

Here is a link to a very educational  3 minute video about WISE done by the Jet Propulsion Lab at Cal Tech University: http://www.redorbit.com/news/video/space/6/nasas_wise_infrared_satellite_set_to_fly/30147/?src=mrss

A 27 minute news conference about WISE can be viewed at this link at You tube:

http://www.youtube.com/watch?v=6Yxilm4PmdM

I hope you enjoyed learning about WISE and its mission!

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Our task must be to free ourselves... by widening our circle of compassion to embrace all living creatures and the whole of nature and its beauty. -Albert Einstein



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Aim for success, not perfection. Never give up your right to be wrong, because then you will lose the ability to learn new things and move forward with your life. Remember that fear always lurks behind perfectionism. Confronting your fears and allowing yourself the right to be human can, paradoxically, make yourself a happier and more productive person. - Dr. David M. Burns



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Ego's trick is to make us lose sight of our interdependence. That kind of ego-thought gives us a perfect justification to look out only for ourselves. But that is far from the truth. In reality we all depend on each other and we have to help each other. The husband has to help his wife, the wife has to help the husband, the mother has to help her children, and the children are supposed to help the parents too, whether they want to or not.-Gehlek Rinpoche Source: "The Best Buddhist Writing 2005 pg. 165

The hostile attitude of conquering nature ignores the basic interdependence of all things and events---that the world beyond the skin is actually an extension of our own bodies---and will end in destroying the very environment from which we emerge and upon which our whole life depends.