One of UCLA’s astronomers was recently named principal
investigator for a new NASA project that will help scientists and
laypeople wise up to the mysterious ways of the universe.
The new Wide-field Infrared Survey Explorer mission has just
been chosen to move into the first stage of development, setting it
on its way to an intended launch date of June 2008.
WISE is a space telescope that will take over a million pictures
of the universe in infrared light ““ light that is too
“red” for the human eye to see, but is ideal for
looking at objects that give off heat, such as dust clouds,
asteroids and “brown dwarfs,” as well as stars that are
too cool to be seen with visible light.
“The fundamental goal is to produce a sensitive
mid-infrared all-sky survey,” said Peter Eisenhardt, project
scientist for WISE at NASA’s Jet Propulsion Laboratory in
Pasadena.
“Past infrared missions were much less sensitive,”
said Edward Wright, UCLA professor of physics and astronomy and the
lead investigator of the WISE mission.
“In 25 years, infrared detection has gotten so much
better,” he added.
The images WISE will transmit back to Earth every 11 seconds of
its six-month complete sky-scan will be up to 500,000 times more
sensitive than any of the previous infrared cosmos scanning
surveys, according to NASA.
Collecting over a million images, WISE will create a
“map” that will help scientists point more
detail-oriented telescopes ““ such as the infrared space
telescope Spitzer, launched in August 2003 ““ at ultraluminous
galaxies and cool stars that cannot be seen with visible light.
“We have a very straightforward observing plan: scan the
whole sky,” Eisenhardt said. “Whereas Spitzer’s
looking at individual targets in more detail (that make up) about
half a percent of the sky.”
But WISE will go beyond creating a map of the cosmos.
The project will also shed light on controversial issues such as
the ways that planets and stars are formed and the age of the
universe.
“There are regions like the Orion Nebula where stars are
forming right now. We can see them forming with infrared
light,” Wright said.
Wright and his team also hope to discover stars that are lurking
undetected in the neighborhood of our solar system.
Brown dwarfs, which are too cold to be detected with visible
light, are thought to be the most common type of star in the
universe, “with an estimated two brown dwarfs for every
hotter star we can detect,” according to Eisenhardt.
“We know that most stars are so cool they can’t be
seen with visible light,” he said.
Our sun’s nearest neighbor is Proxima Centauri, whose
light takes only four years to reach us ““ but WISE may
uncover stars that are even closer.
“There’s a chance we’ll see a star closer than
that,” Eisenhardt said, explaining that there are probably
dozens of cooler star systems that are relatively close by.
“I do hope we can find that,” Eisenhardt said,
“that would be very cool.”
The advantage of sending the telescope out into space,
Eisenhardt said, is that it reduces much of the interference
produced by the atmosphere.
“Ordinary room temperature objects are bright in the
infrared,” Eisenhardt said, explaining that getting above the
atmosphere into cooler space and using a cooling system that
includes what he describes as a “supersize thermos
bottle” to keep the instruments cool provides infrared images
that are 10 million times clearer than those scientists take from
the ground.
WISE will also extend our knowledge about how stars and planets
are formed, Eisenhardt said.
“Sometimes we see an excess of infrared emission coming
from a dusty disk around a star,” Eisenhardt said.
“(By looking at the brown dwarfs) we’ll find out
more about how stars form, but perhaps also what prevents stars
from forming,” he said.
As stars that do not have enough mass to emit much visible
light, brown dwarfs “span the transition between ordinary
stars like the Sun and planets like Jupiter.”
“We can’t see that much of our galaxy,”
Eisenhardt said, explaining that clouds of dust floating around
block much of the light we can see with our eyes and prevent us
from seeing very much of our galaxy. Since infrared light passes
through dust, scientists can use WISE’s images to learn more
about the structure of our galaxy.
“Infrared light is not bothered by that dust,”
Eisenhardt said. “With WISE, we’ll be able to see
basically the whole galaxy.”
WISE will also provide information that will help scientists
continue to grapple with the centuries-old question of how the
universe is structured.
By gathering more information about how cosmic objects interact
with one another, WISE will allow scientists to study the effects
of the invisible but theoretically existent “dark
energy” on matter we can detect.
“Dark energy is the stuff … well, it’s the name we
give to the fact that the universe is accelerating,”
Eisenhardt said.
“We like to think that we’re important, that the
elements we’re made of are important,” Wright said.
“But only 4 percent of the universe is the stuff that you
study in chemistry.”
“Dark energy is three-quarters of the universe,”
Wright said. “It’s really is a very strange universe
indeed.”
Eisenhardt said there is still one more hurdle ahead of the NASA
project, and that is the final construction of a satellite.