NASA makes a 12-year time-lapse of the entire sky

POT created what is essentially a time-lapse of the sky showing changes over a decade using images taken by his space observatory. NEOVIZ.

Every six months, the Near-Earth Object Wide Field Infrared Survey Explorer spacecraft travels to the center of the Sun, taking pictures in all directions. Together, these images form an “all-sky” map that shows the location and brightness of hundreds of millions of objects. Based on 18 all-sky maps prepared by the spacecraft (the 19th and 20th will be released in March 2023), a film is made available on Youtube.

sky maps

Each map is a great resource for astronomers, but viewed sequentially as a span of time, they serve as an even stronger resource for trying to better understand the universe. Map comparisons can reveal distant objects that have changed position or brightness over time, known as time-domain astronomy.

“If you go out and look at the night sky, it may seem like nothing is changing, but it isn’t,” said Amy Mainzer, lead researcher NEOVIZ at the University of Arizona in Tucson. “Stars shine and explode. Asteroids fly by. Black holes tear stars apart. The universe is a very busy and active place.”

NEOVIZ was originally a data processing project to obtain asteroid detection and characterization data from WISE, an observatory launched in 2009 tasked with scanning the entire sky to find and study objects outside our solar system. The spacecraft used cryogenically cooled detectors, making them sensitive to infrared light.

Infrared light, invisible to the human eye, is emitted by many cosmic objects, including nearby cool stars and some of the brightest galaxies in the universe. The WISE mission ended in 2011 after running out of onboard coolant needed for some infrared observations, but the spacecraft and some of its infrared detectors were still operational. Yes, in 2013. POT reused it to track asteroids and other near-Earth objects, or NEOs. Both the mission and the spacecraft have been given a new name: NEOVIZ.

New models

Despite the changes, the infrared telescope continued to scan the sky every six months, and astronomers continued to use the data to study objects outside our solar system.

For example, in 2020, scientists launched the second version of the project called CatWISE: object catalog of 12 maps of the entire sky NEOVIZ. The researchers use the catalog to study brown dwarfs, a galaxy-wide population of objects that lurk in the darkness near our Sun. Although they form like stars, brown dwarfs do not have enough mass to initiate fusion. shine.

Because of their proximity to Earth, nearby brown dwarfs move faster across the sky than more distant stars moving at the same speed. So one way to identify brown dwarfs among the billions of objects in the catalog is to look for moving objects. Additional project to CatWISE titled Backyard Worlds: Planet 9 invites citizen scientists to leak data NEOVIZ searching for moving objects that the computer search might have missed.

with both cards WISE The originals of the entire sky, scientists have discovered about 200 brown dwarfs just 65 light-years from our Sun. Additional maps revealed 60 more and doubled the number of known Y dwarfs, the coldest brown dwarfs. Compared to warmer brown dwarfs, Y dwarfs may have a weirder history in terms of how and when they formed. These discoveries help shed light on the collection of objects in our sunny neighborhood. And a more complete count of brown dwarfs close to the Sun tells scientists how efficient star formation is in our galaxy and when it started.

Watching the sky change over a period of more than a decade has also contributed to the study of how stars form. NEOVIZ he can peer into the dusty sheets covering protostars, or into balls of hot gas that are about to become stars. As the years pass, protostars twinkle and light up, picking up more mass from the surrounding dust clouds. Scientists conduct long-term observation of nearly 1,000 protostars using NEOVIZ for information about the early stages of star formation.

Data from NEOVIZ they also improved the understanding of black holes. The study WISE the original discovered millions of supermassive black holes at the centers of distant galaxies. In a recent study, researchers used data NEOVIZ and a technique called echo mapping to measure the size of disks of hot, glowing gas surrounding distant black holes that are too small and too far away for any telescope to resolve.

“We never expected the spacecraft to last this long, and I don’t think we could have foreseen the science we could do with this amount of data,” said Peter Eisenhardt, an astronomer at NASA’s Jet Propulsion Laboratory. (Jet Propulsion Laboratory). POT and project scientist WISE. (EuropePress)

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