The size of asteroid 2011 UL21 is larger than 99% of the near-Earth asteroids that have been recorded. Asteroid 2011 UL21 is likely five times smaller than the asteroid that caused the extinction of dinosaurs about 66 million years ago, and ten times smaller than the Vredefort asteroid, which is the largest space rock ever to hit Earth.

Although not as powerful as the two asteroids mentioned earlier, the impact of the asteroid collision 2011 UL21 still has the potential to cause significant damage to Planet Earth. This includes the release of debris into the Earth's atmosphere, which can result in major climate changes. Therefore, asteroid 2011 UL21 is often referred to as the "Planet Killer."

Although not posing a current threat, asteroid 2011 UL21 remains interesting to monitor. Gianluca Masi, an Astrophysics expert and Director of the Virtual Telescope Project, noted that 2011 UL21 is one of the 10 largest asteroids approaching Earth within a distance of 4.7 million km since 1900. This was reported by Live Science on Wednesday, June 26, 2024.

Friends of Dream can witness the arrival of asteroid 2011 UL21 through livestreaming provided by VTP. This livestream will start on June 27, 2024 at 03.00 WIB. Alternatively, Friends of Dream can also observe this asteroid directly using a telescope on June 28 and 29 when the asteroid reaches its peak brightness.