The 70-meter Goldstone antenna in the Mojave Desert has begun observations of 2007 TU24, the asteroid that will pass 538,000 kilometers from the Earth on January 27-28. Early indications are that the object is asymmetrical, with a diameter of approximately 250 meters. Close pass by the Earth is to occur on January 29 at 0833 UTC, with no chance of a strike. Says JPL’s Steve Ostro:

“With these first radar observations finished, we can guarantee that next week’s 1.4-lunar-distance approach is the closest until at least the end of the next century. It is also the asteroid’s closest Earth approach for more than 2,000 years.”

Image: These low-resolution radar images of asteroid 2007 TU24 were taken over a few hours by the Goldstone Solar System Radar Telescope in California’s Mojave Desert. Image resolution is approximately 20-meters per pixel. Next week, the plan is to have a combination of several telescopes provide higher resolution images. Credit: NASA/JPL-Caltech.

Now we can anticipate more detailed observations from the Arecibo Observatory, whose radar is the most sensitive in the world, allowing still closer readings on the asteroid’s size. With an imaging mode that offers resolution to 7.5 meters, scientists there should also be able to map the object’s surface in some detail. That’s useful information as we wait for the kind of detailed exploration a dedicated asteroid mission will one day make possible. Arecibo’s Mike Nolan looks forward to an observing session of the kind rarely afforded to those who study asteroids:

“Because it’s coming so close, we’ll get our highest quality imaging…We have good images of a couple dozen objects like this, and for about one in 10, we see something we’ve never seen before. We really haven’t sampled the population enough to know what’s out there.”

And this is worth thinking about: Nolan points out that although objects like 2007 TU24 pass near the Earth every five years on average, astronomers rarely get enough advanced notice to run rigorous observing sessions on them. Finding, classifying and cataloguing such objects is obviously vital, as is continuation of Arecibo’s planetary radar program. Far less helpful is the e-mail hoax making the rounds claiming yet another NASA cover-up, this one of 2007 TU24’s supposedly impending impact. Astronomy.com’s Daniel Pendick has seen that one, but also a far more interesting new video on planetary defense.