On 29 June two large asteroids made a relatively close pass by Earth, making astronomers take a closer look at these celestial wanderers. It was a great opportunity to take a closer look at these potentially hazardous asteroids. Both asteroids are under “Potentially Hazardous Asteroid” due to their predicted close pass with Earth.
Using a 230-foot-wide Goldstone radar system in California, NASA takes a closer look at asteroids. This telescope transmits radio waves at the asteroids and receives the reflected signals to the same antenna. By using this cutting-edge technology NASA creates images of what the asteroids look like.
Asteroid 2024 MK
Two asteroids are Asteroid 2024 MK and another Asteroid, 2011 UL21. Asteroid 2024 MK came within 184,000 miles of our planet—less than the distance between the Moon and Earth. It is 500 feet wide about 150 meters medium-sized asteroid could cause significant damage to our Earth if it collides with Earth.
Using radar system technology, NASA captured detailed images of the Asteroid 2024 MK’s surface, revealing concavities, ridges, and boulders about 30 feet wide. This asteroid 2024 MK was discovered on 16 June 2024, only 13 days before it passed Earth.
Astronomers said it poses no risk to our planet Earth but the problem is it was discovered so late. It highlights our weaknesses in detecting potentially hazardous objects in our cosmic neighborhood. It can be visible through small telescopes.
Asteroid 2011 UL21
Asteroid 2011 UL21 is much larger than asteroid 2024 MK. Its size measures almost a mile wide or approximately 1.5 kilometers. It is classified as a Near Earth Asteroid (NEA). It passed the Earth on 27 June, at 20:14 UTC (22:14 CEST). It is larger than 99% of all known (NEOs) Near-Earth objects, but it poses no risk to Earth and it passed by more than 17 times as far away as the Moon.
This asteroid orbits the Sun every 1,130 days or 3.09 years and comes as close as 0.74 AU (Astronomical Unit- the distance between Earth and the Sun) and reaches as far as 3.51 AU from the Sun. Asteroid 2011 UL21 completes a rotation on its axis every 2.73 hours. Its orbit is 0.02 AU from Earth’s orbit at its closest point.
Future Close Approaches of Asteroid 2011 UL21
| Date | Velocity in Km/s | Distance from Earth in Km |
| June 25, 2089 | 24.957 | 2,666,337 |
| July 1, 2123 | 27.043 | 14,848,598 |
| June 16, 2154 | 21.942 | 25,937,869 |
| June 22, 2188 | 24.064 | 8,046,580 |
NASA’s radio wave imaging revealed that asteroid 2011 UL21 is roughly spherical and has a tiny moonlet orbiting it from a distance of about 1.9 miles or 3 kms. This moonlet’s presence may provide valuable insights into how the asteroid formed.
Both asteroids fall into the category of “potentially hazardous asteroids,” meaning they are generally not an immediate threat but could become problematic in future. If their trajectories changed due to a collision with another asteroid or other factors.
