Travelers in the Night Eps. 385 & 386: New Aten & Silent ET

0:00It's the 365 Days of Astronomy podcast, coming in 3, 2, 1.

0:22Recently, my Catalina Sky survey teammates Carson Foles and Greg Leonard discovered an Aten asteroid, which orbits the sun once every 272 days on a path that crosses the orbits of Venus and Earth a number of times each year. Aten's account for only about 6% of the Earth-approaching asteroids that asteroid hunters discover. They are relatively dim and difficult to discover because they spend most of their time inside the Earth's orbit, with their sunlit side

0:54facing away from us. For example, Carson and Greg's newly discovered asteroid, 2017 WJ-16, is bright enough for asteroid hunters to track for only about 50 nights every couple of years. It is about 150 feet in diameter and travels on an orbit which can bring it to a bit more than three times the moon's distance from Earth. When 2017 WJ-16 is closer to the sun than Earth, it travels faster than we do, allowing it to catch us and just barely cross our orbit as we both travel

1:31about the sun. In 2020, 2017 WJ-16 will make one of its closer approaches to us when it comes to less than about five times the moon's distance from our home planet. At that time, it will be traveling at 2.9 miles per second relative to us, which is well within the reach of our current rocket technology. I suspect that in the future, if the pattern of colors which 2017 WJ-16 reflects reveals a high metal

2:02or water content, humans will mine it to construct and operate their colonies in space. For travelers in the night, this is Dr. Al Grauer. Go to travelersinthenight.org program 421 for more information.

2:24Oumuamua is the asteroid that zipped by the Earth on a trajectory that started beyond our solar system in truly deep space. After rounding our sun at 97,000 miles per hour, this unusual space rock will continue onward into deep interstellar space. The fact that this reddish object's brightness changes by a factor of 10 every 7.3 hours has been interpreted as being due to an elongated rocket or cigar shape which reflects different amounts of sunlight in our direction as it tumbles through

2:58space. This strange space rock appears to be about 730 feet long and about 100 feet wide. Oumuamua's interstellar path, an unusual shape, prompted breakthrough-listened scientists to use the 300-foot diameter, 8,000-ton Robert C. Byrd Green Bank Telescope to see if Oumuamua is emitting radio signals which could indicate that it is some kind of artifact or spacecraft which passed through our

3:29solar system to check it out. Preliminary analysis of several hours of data with a cluster of supercomputers, do not reveal any signals of artificial origin even though this instrument could detect a cell phone at the space rock's distance in about a minute. Care is being taken to reject signals which could be of human origin as well as those which are not consistent with Oumuamua's speed and location. The hypothesis that this interstellar space rock is an alien space probe is pretty far-fetched. However, how it came to have

4:04its current shape is almost equally hard to imagine. For Travelers in the Night, this is Dr. Al Grauer. Go to travelersinthenight.org program 423 for more information.

4:20You are listening to the 365 Days of Astronomy podcast.

4:32Cool. The 365 Days of Astronomy podcast is produced by the Planetary Science Institute. Audio post-production is by me, Richard Drumm. Project management is by Aviva Yamani. And hosting is donated by LibSyn.com. This content is released under a Creative Commons attribution, non-commercial 4.0 international

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5:35looking forward to unraveling more stories from the universe. With every new discovery from ground-based and space-based observatories and each milestone in space exploration, we come closer to understanding the cosmos and our place within it. Until next time, let the stars guide your curiosity.