Astronomers have many tools for studying the universe: telescopes, satellites, interplanetary spacecraft, and more. The humble human eye is also a key part of the toolkit, as it can often spot patterns or anomalies that algorithms miss. More recently, thanks to the crowdsourcing power of the internet, virtual reality (VR), and thousands of eyes working together, have enhanced the scrutiny of our vision.
Researchers at NASA’s Goddard Space Flight Center recently announced Find One of 10 stars surrounded by a dusty disk of debris – a swirling mass of gas, dust and rock left behind after the earliest stages of planet formation.This result, achieved with the help of VR and citizen scientists, was recently published in astrophysical journal. Findings could help astronomers piece together a timeline of how planetary systems were built.
Fragment disk Covers all stages of planet formation, including the young age when worlds were still embedded in debris from Earth The mess they were born into, the messy process. Although Astronomers have managed to directly see some, most of these young planets are beyond the reach of current telescopes. It takes millions of years to make a planetary system, so each debris disk an observer sees is just a brief snapshot of a moment in the system’s life. To unravel the whole story, astronomers searched for many disk planetary systems at various stages of evolution, collecting multiple snapshots to piece together on a timeline.
To look for debris disks, observers typically first look for stars that appear particularly bright in the infrared. This unusual brightness usually comes from excess starlight heating dust in the disk around the star. NASA’s infrared telescope WISE (Wide Field Infrared Survey Explorer) Toured the entire sky, creating in some ways the most comprehensive catalog of stellar infrared measurements to date. With tens of thousands of data points to analyze, and possibly many disks of debris hidden in the WISE catalog, what should scientists do?
“This is a great example of how modern astronomy is looking for the proverbial needle in a haystack in massive datasets,” said Meredith HughesAn astronomer at Wesleyan University, who was not involved in the study. “Even with machine learning algorithms, it’s still difficult to train computers to do the complex job of recognizing noisy patterns and noticing subtle deviations from expectations, which is where the collective intelligence of citizen science comes into play.”
A project called Disk Detective trains citizen scientists (regular people who want to help with research in their spare time) to look at WISE images and compare them to images from other astronomical surveys, such as SkyMapper Southern Sky SurveyThis Pan-Star Survey and Two Micron All-sky Survey (2MASS), to confirm the presence of a disk around each candidate star. Since the project started in 2014, citizen scientists have discovered more than 40,000 disks — 40,000 snapshots of planetary history.
To incorporate these into the timeline, however, astronomers need to figure out where each snapshot belongs. In other words, scientists need to know the age of each star and its debris disk. “When we know the ages of stars and planets, we can put them in order — from babies to teens to adults, if you will,” said Mark Kuchner, NASA astrophysicist and co-author of the new study. “This allows us to understand how they form and evolve.”
Determining the age of stars in any reasonably precise way is a notoriously thorny problem in astronomy. One solution is to match a star with its siblings in an association called a moving group. Stars typically form clusters from a huge cloud of gas, but many of these once-close families of stars have split up with age, with their individual members scattered across the Milky Way. By carefully measuring the positions and velocities of stars, researchers can determine which stars show distinct motions that work backwards, indicating that they were born together at the same time and place. Once astronomers know that stars in a population are related, they can directly calculate their ages based on established knowledge about how stars grow and evolve.
Finding new moving team members is not easy. To do this, astronomers have traditionally relied on analyzing pre-existing lists of moving constellations, flagging potential new members through sophisticated mathematical models.The team behind the new project wanted to try something different and more internal: it used a virtual reality program Zoom around the stars and get a clearer three-dimensional view of how things are moving.
“I thought I’d be scared [NASA’s VR scientists] When I said I wanted to visualize the positions and velocities of four million stars, I left,” Kuchner said. “But they didn’t even have an eyelash! ” To create this virtual stellar cornucopia, the team used Gaia, a satellite of the European Space Agency that provides the best possible measurements of the positions and velocities of stars in our galaxy. The resulting virtual-reality simulations also acted as a kind of time machine—knowing how fast and in which direction a star was moving, allowing Kuchner and his colleagues to track its back-and-forth motion in time.
While working as a visiting researcher at NASA, lead study author Susan Higashio donned a VR headset and flew around a simulated millions of stars. She examined the relationship of stars with disks to groups of known motions and deduced the forward and backward motions of the stars in time to test their potential associations. “It was so exciting when 4 million stars appeared in VR, but when they all started spinning around me, I felt a little dizzy,” she recalls. “It’s a really fun and interactive way to do science.”
Higashio traced Disk Detective’s 10 fragmented disks to their move group family. The team then found the estimated ages of the disks, which ranged from 18 million to 133 million years old. Compared to our solar system, they are all very young, about 4.5 billion years old. The researchers also discovered an entirely new moving group, called Smethells 165, named after its brightest star. “Every time we find a new moving group, that’s a new batch of stars whose age we know more accurately,” Kuchner explained.
Astronomers also discovered a strange, extreme debris disk around a star nicknamed J0925 that doesn’t quite fit their expected timeline of planet formation. It’s much brighter in the infrared than would be expected from a star of its age — meaning it has more dust.As the debris disks get older, some of their dust can spiral into the star or be blown away star windHowever, J0925 appears to have just received fresh hot dust, possibly from a collision between two recent protoplanets. Hughes emphasized that the star is the most interesting object found in the study. “Extreme debris disks are still a bit of a mystery, but they may resemble what our solar system looked like during the giant impact that formed Earth’s moon.”
Citizen science work on Disk Detective is still in progress and has now been upgraded to work Gaia’s latest batch of data. The team hopes to identify members of more mobile groups and new disks through their unique VR approach. Lisa Stiller, one of the study’s many citizen scientist co-authors, offers encouragement for future volunteers. “Don’t hesitate to help in citizen science projects,” she said. “Whatever form you choose or choose to dedicate your time, your help is needed.”
Anyone with an internet connection can still join Disk Detective Project, no experience required. “Over 30,000 citizen scientists contributed,” Kuchner said. “Disk Detective is still processing hundreds of thousands of WISE images – we still need your help.”