The clip was produced with a tool called NEOWISE.
It’s not every day that you get to see the entire sky, much
less over a span of 12 years. However, now NASA’s Near-Earth Object Wide Field
Infrared Survey Explorer, or NEOWISE, spacecraft (not to be confused with the
comet) has produced just such a video, according to a press release by NASA.
Images taken in all directions
Every six months, NEOWISE undertakes a trip halfway around
the Sun, taking images in all directions. Astronomers have now stitched
together those images to produce an “all-sky” map showing the location and
brightness of hundreds of millions of objects and revealing changes that span a
decade.
Each map on its own provides plenty of data for astronomers,
but when viewed in sequence as a time-lapse, they serve as an even stronger
resource for trying to better understand the universe by comparing changes in
the maps.
“If you go outside and look at the night sky, it might seem
like nothing ever changes, but that’s not the case,” said Amy Mainzer,
principal investigator for NEOWISE at the University of Arizona in Tucson.
“Stars are flaring and exploding. Asteroids are whizzing by. Black holes are
tearing stars apart. The universe is a really busy, active place.”
In its inception, NEOWISE was tasked with retrieving
asteroid detections and characteristics from WISE (an observatory launched in
2009). The tool made use of cryogenically cooled detectors that made them
sensitive to infrared light.
Infrared light is radiated by many cosmic objects but is not
visible to the human eye. The WISE mission saw its lifespan end in 2011 when
its onboard coolant ran out. However, its spacecraft and some of its infrared
detectors were still functional.
Never wanting to let some good instruments go to waste, in
2013, NASA repurposed WISE to track asteroids and other near-Earth objects and
that’s how NEOWISE was born.
Now, the spacecraft has been watching the sky change for
more than a decade and has also contributed to studies of how stars form.
NEOWISE has the unique ability to see into the dusty blankets swaddling
protostars, or into the balls of hot gas that are well on their way to becoming
stars.
Long-term monitoring of protostars
Today, astronomers are conducting long-term monitoring of
almost 1,000 protostars with NEOWISE to gain insights into the early stages of
star formation.
But that’s not all. Data collected from NEOWISE’ has also
improved understanding of black holes. In more recent research, scientists have
combined NEOWISE data and a technique called echo mapping to measure the size
of disks of hot, glowing gas surrounding distant black holes, which are too
small and too distant for any telescope to identify or image.
“We never anticipated that the spacecraft would be operating this long, and I don’t think we could have anticipated the science we’d be able to do with this much data,” said Peter Eisenhardt, an astronomer at NASA’s Jet Propulsion Laboratory and WISE project scientist.