Travelers In The Night

Using our Schmidt telescope on Mt. Bigelow, Arizona, my Catalina Sky Survey teammate Richard Kowalski was searching for Earth approaching asteroids in the constellation of Virgo when he discovered a moving point of light which had suddenly appeared and was about 40 times brighter than is typical for a near Earth asteroid. 75 hours later, scientists at the Minor Planet Center used data from 17 different observatories around the globe to calculate it's orbit around the Sun, estimate it's size to be 630 feet in diameter, and give it the name 2018 BT6. Three weeks before Richard discovered 2018 BT6, it was very dim with less than 1% of it's illuminated side facing us as it came from the direction of the Sun giving humans little advance notice as it approached us at a speedy 16.4 mi/s. In 2018 this relatively large space rock came to about 18 times the Moon's distance from us. In the future it's orbit can bring it to about 0.6 of the Moon's distance from us. According to the Purdue University and Imperial College of London's impact calculator, one it's size impacts the Earth every 300,000 years or so creating a crater in sedimentary rock 7 miles in diameter and 2,000 feet deep. Fortunately 2018 BT6 will not strike the Earth in the foreseeable future, however, it's discovery presents us with the fact that currently humans would have little advance warning of the impact of a relatively large space rock if it approached us from the direction of our Sun.

Asteroid hunters find asteroids by looking for objects which change their position relative to the stars.  If an asteroid happened to match the Earth’s motion it might appear stationary and thus be virtually undetectable until it is right on top of us. The trick is finding potentially dangerous asteroids at some other point in their orbit so we know about them before they have a chance to approach Earth.

Most of the humans on planet Earth have never witnessed that the natural night sky is not dark; but rather it is alive with it's own lights. To see for yourself, pick a dark sky place near you like the Cosmic Campground International Dark Sky Sanctuary from the International Dark Sky Association's website, darksky.org, and recruit a friend. Do a bit of research on how to achieve and sustain your night vision. Bring a red filtered flashlight, reclining lawn chair, star maps, binoculars, warm clothes, a telescope if you have one, and snacks. Keep on the look out for special events. The American Meteor Society's website will let you know when to expect meteor showers. Most humans have never seen the glowing light pyramid called the Zodiacal light which is produced by ice particles and dust in the solar system. In the northern hemisphere it is prominent in the evening sky in February, March and April. During the same months it lights up the predawn sky in the southern hemisphere. Star clusters scattered around the sky can be enjoyed with binoculars or a small telescope. New Moon's from May through October will provide you opportunities to explore the Milky Way with your naked eye or pair of binoculars. This adventure will fill you with wonder at what might be out there. Last but not least Mars will dominate the night sky during much of 2018 as it and the Earth come near to each other. For a time in late July of 2018 Mars will even outshine the giant planet Jupiter in the night sky.

My Catalina Sky Survey teammate Josh Hogan was asteroid hunting in the constellation of Ursa Major with our small but mighty Schmidt telescope when he spotted a fast moving point of light in a set of his images and posted his observations on the  Near Earth Object Confirmation Page or NEOCP for short. The NASA Sentry software system automatically scans the NEOCP and from the initial observations of Josh’s discovery predicted there was a tiny minuscule but non zero chance that it could impact our home planet in the next 100 years. Asteroid hunters were able to show that 2026 GB is not a threat only after they had accumulated enough data to accurately determine its orbit which demonstrates that planetary defense is by necessity an international effort.

On December 25, 2017, while searching for Earth approaching asteroids in the constellation of Virgo, the Universe gave my Catalina Sky Survey teammate Greg Leonard a Christmas present in the form of a comet which now bears his name. Comet P/2017 Y3 (Leonard) orbits the Sun once every 31 years on a highly elliptical path which takes it from between the orbits of Earth and Mars out to almost the planet Uranus's average distance from the Sun. Since it has been observed for only a very short piece of it's path about the Sun, it is not possible to accurately predict Comet Leonard's location very far into the future. In 2017 and 2018 it appeared as a faint fuzzy point of light in the night sky and never came came closer than about 150 million miles from Earth. Comet Leonard's next visit to our neighborhood will be in 2033 or 2034. At some point in the future it's orbit could bring much closer to Earth as it comes into the inner solar system about twice every human lifetime. Greg's comet is classified as a Halley family comet and although it is difficult to predict how a comet will brighten as it approaches the Sun, it is unlikely that it will ever become as bright as it's famous cousin. That situation could change when Comet Leonard comes near the giant planet Jupiter. In the past Jupiter has sent Comets in our direction or ejected them from the solar system. Only time will tell.
For Travelers in the Night this is Dr. Al Grauer.