Subaru Telescope Confirms Asteroid 2024 YR4 Is Safe from Earth Impact: No Collision Threat

Asteroid 2024 YR4: From Impact Risk to Safe Passage

In late December 2024, the newly discovered Near-Earth Asteroid (NEA) 2024 YR₄ sparked concern when initial observations suggested a potential, albeit small, risk of impacting Earth in December 2032.Detected by the Asteroid Terrestrial-impact Last Alert System (ATLAS) in Chile on Dec. 27, 2024, the Apollo-group asteroid, which completes an orbit around the Sun every four years, prompted the International asteroid Warning Network (IAWN) to issue an impact risk notification.

Refined Observations Allay Impact fears

Following the initial alert, observatories worldwide, including the Subaru Telescope in Hawaii, focused on gathering additional data to refine 2024 YR₄‘s trajectory. On Feb. 20, 2025, the Subaru Telescope captured crucial images that, when combined with other data, allowed astronomers to significantly reduce the estimated impact probability to a negligible 0.004%.

Revised calculations from NASA’s Center for NEO Studies (CNEOS), the ESA’s Near-Earth Objects Coordination Centre (NEOCC), and the NEO Dynamic Site (NEODyS) confirmed the reduced risk. The asteroid will now “pass at a distance beyond the geosynchronous satellites and possibly beyond the moon,” according to IAWN reports.

The Role of the Subaru Telescope and Hyper Suprime-Cam

The Subaru Telescope’s contribution was pivotal. Equipped with the Hyper suprime-cam (HSC), a wide-field prime-focus camera, the telescope tracked 2024 YR₄ effectively as it dimmed. Dr. Tsuyoshi Terai of the National Astronomical Observatory of japan (NAOJ), who led the observations, noted the challenge: “Although 2024 YR₄ appeared relatively shining at the time of its discovery, it has been steadily fading as it moves away from the Earth. By late February, observations would have been extremely challenging without a large telescope. This mission was successfully accomplished thanks to the Subaru Telescope’s powerful light-gathering capability and HSC’s high imaging performance.”

IAWN’s Continued Vigilance and Future Observations

The IAWN continued tracking 2024 YR₄ through early April 2025. After that, the asteroid will become too faint for observation until 2028 when it will be within range of Earth-based telescopes again.

Impact Risk Fluctuations and Planetary Defense

Throughout February 2025, estimations of the asteroid’s impact probability fluctuated.Initial concerns of a 1% chance of impact in 2032 evolved to a high of 3.1% before eventually dropping to 0.004%. This underscores the importance of continuous monitoring and advanced observation capabilities in planetary defense.

these refined measurements, conducted at the request of the JAXA Planetary Defense Team, initially indicated a higher risk of 2.3%, then 3.1%, before settling at the final, significantly lower probability. The fluctuations highlight the dynamic nature of near-Earth object (NEO) tracking and the constant refinement of orbital calculations.

Monte Carlo modeling of 2024 YR4’s swath of possible locations as of February 23rd, 2025 – 0.004% probability of impact. Credit: iawn.net

Looking Ahead: Continuous Monitoring and Planetary Safety

While 2024 YR₄ no longer poses a threat,the episode serves as a crucial reminder of the importance of ongoing efforts in NEO detection and tracking. Agencies like NASA,ESA,and international collaborations such as the IAWN play a vital role in safeguarding our planet. The data gathered from these observations not only allows scientists to predict potential risks but also advances our understanding of the solar system and the objects that populate it.

Stay informed about future NEO updates. Follow space agencies and astronomical organizations for the latest discoveries and risk assessments. By supporting these initiatives, you contribute to the ongoing effort to protect our planet from potential asteroid impacts.

Given the discussion on private space companies’ role in asteroid detection, what are Dr. Thorne’s thoughts on their involvement in planetary defense efforts?

near-Earth asteroid 2024 YR4: An Interview wiht Dr. Aris Thorne

Recently, the Near-earth Asteroid (NEA) 2024 YR4 made headlines due to a brief period of concern about a potential future impact. Fortunately,further observations substantially reduced that risk. We sat down with Dr. Aris thorne, a planetary defense specialist from the International Asteroid Warning Network (IAWN), to discuss the recent events surrounding 2024 YR4 and the importance of planetary defense.

The Initial Discovery and Concern

archyde: Dr. Thorne, thank you for joining us. Can you walk us through what happened when 2024 YR4 was initially discovered?

Dr. Thorne: Certainly. 2024 YR4 was detected by the ATLAS system in Chile in late December 2024. Initial observations suggested a very slight chance of a potential impact in December 2032. as an Apollo-group asteroid, these near-Earth objects require careful monitoring, which prompted IAWN to issue a standard impact risk notification.

Refining the Trajectory: The Role of Observation

Archyde: We understand observatories around the world then sprang into action. What role did observations play in refining 2024 YR4’s trajectory?

Dr. Thorne: Observations are absolutely critical. They provided the data needed to improve our understanding of the asteroid’s orbit. Specifically, the Subaru Telescope in Hawaii, equipped with the Hyper Suprime-Cam (HSC), captured crucial images that, when combined with data from other observatories, allowed us to dramatically reduce the estimated impact probability.

The Subaru Telescope and Hyper Suprime-Cam’s Contribution

Archyde: Could you elaborate on the role the Subaru Telescope specifically played?

Dr. Thorne: The Subaru Telescope, with its powerful light-gathering capability and the HSC’s wide field of view, was instrumental. As Dr.Tsuyoshi Terai from NAOJ noted, 2024 YR4 was fading rapidly. Without a large telescope like Subaru,tracking it would have become extremely difficult in late february. The HSC’s high imaging performance was essential for precisely measuring the asteroid’s position.

Impact Probability Fluctuations and the Dynamic Nature of NEO Tracking

Archyde: The impact probability estimates seemed to fluctuate quite a bit. What caused those fluctuations and what does that say about NEO tracking?

Dr. Thorne: That’s an excellent point. Initial estimations suggested around a 1% chance of impact, which then rose to 3.1% before ultimately dropping to a negligible 0.004%. these fluctuations are a normal part of the process. As we gather more data, our calculations become more precise.this episode highlights the dynamic nature of near-Earth object tracking and the continuous refinement of orbital calculations. The refined measurements, conducted at the request of the JAXA Planetary Defense Team, showcase the importance of collaborative efforts.

The Importance of Continuous Monitoring and Planetary Defense

Archyde: So, with the risk now significantly reduced, what’s the takeaway from this experience?

Dr. Thorne: While 2024 YR4 no longer poses a foreseeable threat, it serves as a critical reminder of the importance of continuous monitoring and advanced observation capabilities for planetary defense.Organizations like NASA, ESA, JAXA, and initiatives like the IAWN play a vital role in safeguarding our planet. Understanding the threat landscape created by near-Earth asteroids through ongoing efforts in NEO detection and tracking is paramount.

Looking Ahead: Future Observations and Public Engagement

Archyde: What’s next for 2024 YR4 and planetary defense in general?

Dr. Thorne: IAWN continued observing 2024 YR4 into early April 2025 when the asteroid became too faint, before it will be within observational range again in 2028. The episode underscores that continuous monitoring is not just about immediate threats; it’s also about building a comprehensive understanding of the long-term dynamics of our solar system. We also encourage the public to stay informed about NEO updates by following space agencies and astronomical organizations. By supporting these initiatives, everyone can contribute to protecting our planet from potential asteroid impacts. What are your thoughts on private space companies helping with asteroid detection?