Will an asteroid collide with Earth? How the Webb telescope will track 2024 YR4
The race to understand more about the asteroid that − as of now − has a 1.8% chance of colliding with the Earth in December 2032 is getting a boost from a heavy hitter in celestial observation: the James Webb Space Telescope.
In a blog post Monday confirming that the telescope would observe the near-Earth asteroid − known as 2024 YR4 − the European Space Agency (ESA) said the telescope will help astronomers more precisely determine the asteroid's size and temperature as the asteroid's orbit takes it farther from the sun. The asteroid is moving away from Earth now on its orbital path, so a larger telescope like Webb can help narrow down the asteroid's true trajectory.
The Webb telescope, launched in 2021 as an international partnership of NASA, the ESA and the Canadian Space Agency, brings with it several advantages over the Earth-based telescopes tracking the asteroid: its ability to perceive light from a large swatch of the infrared range of the electromagnetic spectrum and its vantage point 1 million miles from Earth.
What are the chances of of 2024 YR4 colliding with Earth?
Very small − for now. More recent observational data last week put the chances of a collision with Earth at 1.8%, up slightly from the 1.2% estimate published Jan. 29. But researchers expect that additional data and observations will help astronomers refine the asteroid's trajectory.
At present, the line of 500 possible asteroid positions (pictured below) on Dec. 22, 2032, measures 1.2 million miles long. The risk assessment of 1.8% is just the ratio of the Earth's diameter to that line.
According to an ESA blog from Feb. 6, by the end of this month the object will be "too faint for even professional, 4 m-class telescopes to see," which makes the use of the Web telescope in refining calculations even more crucial.
How large is 2024 YR4?
An analysis by NASA's JPL/CNEOS has estimated the asteroid to be anywhere from 130 to 300 feet wide, a figure that hasn't changed much since the object's discovery on Dec. 27. It was first spotted at the Asteroid Terrestrial-Impact Last Alert System (ATLAS) telescope in Rio Hurtado, Chile.
At that size, the ESA published in a Jan. 29 statement, an impact on Earth "could cause severe damage to a local region."
"It is very important that we improve our size estimate for 2024 YR4: the hazard represented by a 40 m asteroid is very different from that of a 90 m asteroid," the ESA wrote in a blog post Feb. 10.
Asteroid 2024 YR4 also rates 3 of 10 on the Torino Impact Hazard Scale, a method for astronomers to categorize and rate the threat of near-Earth objects
Where is the asteroid now?
2024 YR4 follows an elliptical orbit around the sun. Though current projections don't pose an immediate impact threat to Earth, its orbit does bring it close to Earth's orbit on occasion.
“It is rare to have an asteroid with a non-zero probability of hitting Earth,” Heidi Hammel, vice president of the Planetary Society’s board of directors, said in a news release. “At this point, astronomers have measured the object’s orbit, and further observations will refine that orbit to give us a more precise understanding of its potential danger."
How will the James Webb Space Telescope help track 2024 YR4?
The Webb Telescope launched Christmas Day in 2021 and made a splash seven months later when the first images were released in July 2022. The $10 billion observatory was designed to perceive a broader range of light from the infrared spectrum and has four main instruments in its Integrated Science Instrument Module, or ISIM.
Two of these instruments, the Near-Infrared Camera (NIRCam) and Mid-Infrared Instrument (MIRI), will help astronomers track 2024 YR4's position and size, and better inform NASA and ESA of any hazards of its orbital path.
The Webb Telescope, whose observational time is in high demand from institutions worldwide, has observational time set aside for teams with time-critical discoveries, like 2024 YR4.
Contributing: Eric Lagatta
SOURCES: NASA Jet Propulsion Laboratory, Center for Near Earth Object Studies (CNEOS); European Space Agency; Reuters