Archive

Archive for February 11, 2025

Ephemeris: 02/11/2025 – Newly discovered asteroid may have our number

February 11, 2025 Comments off

This is Ephemeris for Tuesday, February 11th. Today the Sun will be up for 10 hours and 17 minutes, setting at 6:06, and it will rise tomorrow at 7:47. The Moon, 1 day before full, will set at 8:06 tomorrow morning.

Late last year a tiny asteroid was found because it was close to the Earth and given the designation 2024 YR4. After observing it for a month it was discovered that it had a 1½ % chance of hitting the Earth when it came around again in 2032. Remember the fireball that exploded over Chelyabinsk Russia almost exactly 10 years ago? It exploded high in the air, and caused flying glass injuries to over a thousand people who saw the flash and rushed to the windows to see it when the atmospheric shock wave arrived. This object appears to be about 3 times the size of that object, nearly a football field in diameter, and thus could be 27 times the mass and volume. It’s four year orbit of the Sun will bring it back close to Earth in 2028 for us to get a better look at it and its orbit, and the last chance to alter its orbit.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EST, UT – 5 hours). Times will be different for other locations.

Addendum

The orbit of the asteroid 2024 YR 4 is shown with the orbits of the planets of the inner solar system in this plot from the Jet Propulsion Laboratory's Small Body Database
The orbit of the asteroid 2024 YR 4 is shown with the orbits of the planets of the inner solar system in this plot from the Jet Propulsion Laboratory’s (JPL) Small Body Database. I’ve added the arrow to the orbit intersect point, where the orbits of this asteroid and the Earth cross each other. That is where the Earth is around December 22nd each year. The asteroid and the Earth will be in about the same position 4 years from now. It would be a good time if the asteroid is close enough to the Earth to get an accurate measurement of its diameter, which is currently estimated based on the asteroid’s brightness. Most asteroids have the reflectance, or what astronomers called albedo of something like a charcoal briquette. But it does vary from asteroid to asteroid based on their composition. If the asteroid gets close enough, radar measurements will tell us for sure its size and give us a more accurate position which will affect the accuracy of where the asteroid will come through in 2032. Currently the possible error in the predictions is an area larger the orbit of the Moon. The Moon is about 60 times the radius of the Earth away.

Categories: Asteroid, Ephemeris Program, The Earth Tags: