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Recently my Catalina Sky Survey teammates Carson Fuls and Greg Lenoard discovered an Aten asteroid which orbits the Sun once every 272 days and on a path that crosses the orbits of Venus and Earth a number of times each year. Atens 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 facing away from us. For example Carson and Greg's newly discovered asteroid, 2017 WJ16, 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 WJ16 is closer to the Sun than Earth it travels faster then we do allowing it to catch and just barely cross our orbit as we both travel about the Sun. In 2020, 2017 WJ16 will make one of it's closer approaches to us when it comes to about less than 5 times the Moon's distance from our home planet. At that time it will be traveling at 2.9 miles/second relative to us which is well within reach of our current rocket technology. I suspect that in the future if the pattern of colors which 2017 WJ16 reflects, reveals a high metal or water content humans will mine it to construct and operate their colonies in space.

According to NASA an average of one catalogued piece of space junk per day has come down to Earth over the past 50 years. Research is described which can track space junk in the atmosphere and provide the starting location and altitude for tracking clouds of environmentally problematic toxic chemical and/or nuclear contaminants released by the disintegration of reentering spacecraft.

The NASA Curiosity Rover has shown us evidence of ancient rivers and bodies of liquid water on the martian surface. Given it's thin cold atmosphere, seeps of liquid water, presently on the surface of Mars which are capable of hosting microbial life appear to be unlikely. Scientists were thus surprised when high resolution imaging of the red planet's surface revealed thousands of intriguing dark streaks called RSL on hundreds of rocky slope areas. These fascinating features slowly extend down hill and grow during the martian warm season, fade during the colder season, and reappear during the next martian warm period. On Earth features like these are produced by seeps of liquid water. However, on Mars a careful study of 151 RSL features at ten different sites using the high resolution camera on NASA's Mars Reconnaissance Orbiter reveal that they occur almost entirely on slopes which are greater than 27 degrees. This new research published in Nature Geoscience suggests that RSL are composed of solid particles in dry granular flows which unlike water seeps appear to end on many of the dunes when it's slope falls below a critical value. What makes RSL tick remains a mystery and likely involves small amounts of water trapped from the atmosphere. Currently surface conditions are hostile to life as we know it, however, the possibility of finding evidence of ancient life or perhaps even still existing microbe colonies in deep sub surface pockets of water are reasons to continue to explore our next door neighbor without contaminating it.

On a recent night my Catalina Sky Survey teammate Vivian Carvajal found 4 Earth approaching space rocks with our small but mighty Schmidt telescope on Mt. Bigelow, Arizona. These Earth approaching asteroids are all small with an average diameter about the width of tennis court. On their current paths none of them come closer than about 4 lunar distances from our home planet.

In 2012 as it crossed the orbit of Neptune heading towards the Sun a small space rock was 250 times fainter than can be detected by the Hubble Space Telescope. Five years later, after it had rounded the Sun, it became visible in asteroid hunter's telescopes for about 16 days, as it streaked across our planet's orbit at 37 miles per second, as it continued to move away from the Sun. During that brief period of time it was discovered by the PanSTARRS group in Hawaii, tracked by telescopes around the world, and given the name Oumuamua (“Oh-moo-ah-moo-ah”). Turns out that previous to the discovery observations, sightings too sparse to report, were obtained by my team using the Catalina Sky Survey's Schmidt telescope on Mt. Bigelow, Arizona. In 2024 this unusual space rock will cross Pluto's average distance from the Sun traveling on a path which will take it into deep interstellar space. Since we don't know how Oumuamua could obtained it's current trajectory from processes in our solar system, it is safe to presume that it originated in truly deep space. The mystery of Oumuamua deepened when astronomers measured it's brightness to change regularly by nearly 10 times over a 7.3 hour period of time. If these brightness variations are due to it's shape, and thus the amount of sun light reflected as it rotates, Oumuamua looks like a cigar. Even though Elon Musk's SpaceX Mars rocket could catch Oumuamua, it is more cost effective is to simply wait to discover another one of the several interstellar asteroids which pass by us each year.

Artificial light at night also known as light pollution is degrading human safety and health as well as damaging the natural environment on which we all depend. The loss of the connection with the natural night sky has happened over the past 100 years. Restoring the natural night sky is relatively simple and can even save money. Before restoration can effectively begin it is essential to make night sky brightness measurements in both natural night sky and urban locations.

Recently there were four fireball meteors, brighter than the planet Venus, which exploded over Germany, France, Ohio, and Arizona within the space of only 10 hours. A total of 1320 individuals were treated to light shows and reported their observations to the American Meteor Society. The one which exploded over Arizona was probably several feet in diameter and entered the Earth's atmosphere over Flagstaff. This event was observed in Arizona, California, Nevada, Utah, New Mexico, and Colorado. It was recorded by numerous electronic security and dashboard cameras and was visible for from 3 to 7 seconds. This meteor also produced a booming sound which was reported by about a dozen different observers. The fireball was last seen over Happy Jack, Arizona and is likely to have produced meteorite fragments which are scattered along Interstate 17 somewhere in the rugged country between Phoenix and Flagstaff. There are likely to be on the order of 1,000 fireball events over the Earth every day. Most of them occur over the oceans or during the day and pass unobserved by humans. During the first 10 months of 2017 the most energetic fireball event occurred when a meteoroid entered the Earth's atmosphere at 8.5 miles/second above the ocean between Australia and Antartica. If you record a fireball with your dash cam or security camera report it to the American Meteor Society. Your data will be very important in finding out where it came from in the solar system as well as to indicate where it might be possible to find pieces of it on the ground.

Humans can mitigate the damage done by the impact of an asteroid given a sufficient lead time. In 1998, the US Congress mandated NASA to detect and track 90% of the 1 km sized asteroids capable of effecting local mass destruction as well as global disruption of agriculture and other human activities. This goal has been accomplished. In 2005 Congress extended the mandate to require NASA to detect and track 90% of the 140-m asteroids capable of destroying a large metropolitan area.

Astronomers continue to be delighted when they discover an Earth sized planet. Scientists were thus very disappointed when the red dwarf star hosting the nearest such planet, Proxima b some 4.2 light years away, turns out to have the nasty habit of emitting bursts of radiation which are likely to sterilize and/or remove the atmospheres of it's family of planets. Recently, hope of finding a nearby Earth was rekindled when scientists at the European Southern observatory in Chile discovered a small planet circling what appears to be a quiet well behaved red dwarf star 11 light years from us. Astronomers are not yet sure that this newly discovered Earth sized planet lies within it's stars habitable zone where liquid water could exist on it's surface. Jumping the gun, ET enthusiasts have beamed a friendly message in the direction of another nearby red dwarf planet system. Their target the super Earth planet, GJ 273b is located some 12.4 light years away near the bright star Sirius in the constellation of Canis Major. At this distance a civilization on GJ 273b could have already received a picture of humanity by deciphering 'I love Lucy' and other TV signals it has been picking up for 50 years or so. The next generation of very large telescopes will allow astronomers to search for the presence of oxygen and other molecules which indicate the presence of life in the atmospheres of nearby worlds. In the mean time we have more reasons to be thankful for what we have here on planet Earth. For Travelers in the Night this is Dr. Al Grauer. Go to travelersinthenight.org program 417 for more information.

My Catalina Sky Survey teammate Tracie Beuden was observing with our Schmidt telescope on Mt. Bigelow, Arizona in the constellation of Persus when she found the first asteroid of 2026. Asteroid hunters are trying to like Tracie's discovery with our number on it far enough in advance so humans could give it a tiny nudge and make it miss Earth.

The orbits of the planets are closely aligned with the extension of the Sun's equator into space and are contained within the flattened disk of material which forms the plane solar system. Most asteroids have orbits with inclinations or tilts to the solar system's plane which are less than 20 degrees. Thus, when my Catalina Sky Survey teammate Rose Matheny discovered a small space rock which soars into the lonely space high above and below our solar system's plane, it got our attention. As with all of our asteroid discoveries, Rose had no idea of what kind of object she had discovered with our Schmidt Telescope on Mt. Bigelow, Arizona until it had been tracked by observers around the world. The Minor Planet Center used the data from 14 different telescopes to calculate an orbit, estimate a size, and give the new object the name, 2017 TF4. Rose's odd ball near Earth Apollo asteroid discovery , 2017 TF4, has an orbit which is tilted by 60 degrees to the plane of our solar system. It's inclination or tilt is greater than 99.5% of the other 8,000 known Earth approaching Apollo asteroids. 2017 TF4, Rose's 260 foot diameter discovery orbits the Sun at about the same distance as the Earth once every 414 days. Perhaps as asteroid hunters discover additional small objects with orbits similar to Rose's discovery we will be able to trace them back to when they were created by a catastrophic collision long ago.

Astronomers using the 8.1 m Gemini South Telescope in Chile were excited by the fact that 467P (LINEAR-Grauer)’s Centaur like orbit had been changed as the nucleus emitted rocket like bursts of gases as it was warmed by the Sun. Inert inactive asteroids orbit the Sun following the law of gravity whereas active asteroids can emit little rocket like bursts of gas which can change their path about the Sun in interesting ways. It is important to study objects like 467P (LINEAR-Grauer) to make sure their path about the Sun doesn’t change to make them a threat to our home planet.

Once every 1,435 days , a 780 foot diameter space rock that my Catalina Sky Survey teammate Carson Fuls discovered makes an annihilation defying close approach to our star. At it's nearest point to the Sun, Carson's well done space rock is traveling at an amazing 93 miles per second and receives 26 times the amount of solar radiation that heats the surface of the planet Mercury to 800F. After Carson first discovered his heat resistant space rock traveling towards it's next hot date with the Sun, it was observed by telescopes in New Mexico, Arizona, Hawaii, and England. These data allowed scientists at the Minor Planet Center to calculate it's orbit around the Sun, estimate it's size, and give it the name 2017 TC1. 2017 TC1 crosses the orbits of Mars, Earth, Venus, and Mercury and can come relatively close to Jupiter on it's extremely elliptical orbit about the Sun. It is possible that in the very distant past the giant planet Jupiter's pull on 2017 TC1 sent it on it's current path around the Sun. In September of 2021, 2017 TC1 will once again be bright enough for asteroid hunters to track as it makes another close approach to our Sun. At this time astronomers with be able to measure the pattern of colors that 2017 TC1 reflects which will reveal it's surface chemical composition. Until then we are left to wonder how it is possible for a space rock to survive on such a harrowing path.

In 1892 the world’s largest telescope, the Lick Observatory’s 36 inch refracting telescope made the news when E.E. Barnard discovered, Amalthea, the 5th moon of Jupiter. In 2025 this historic telescope made the news again when on Christmas morning winds of 114 mph blew off a 3 ton piece of the shutter on its dome.The adaptive optics research pioneered at Lick Observatory helped in the creation of the twin giant 10 meter telescopes that sit atop Mauna Kea in Hawaii.

Without additional data, the true nature of the rapidly northward moving point of light my Catalina Sky Survey teammate Carson Fuls had just discovered would have remained a mystery. Fortunately, this new object was tracked by telescopes in both Arizona and New Mexico. These data were used to calculate it's orbit around the Sun, estimate it's size, and give it the name 2017 UX5. When Carson first spotted this enormous 1,200 foot diameter space rock it was more than 30 million miles away traveling in our direction at 10.7 mi/s. It's orbit and that of the Earth's nearly intersect and at the closest point they are about two and one half times the Moon's distance from us apart. An asteroid the size of 2017 UX5 impacts the Earth every 76,000 years or so. According to the impact calculator developed at Purdue University and the Imperial College of London if 2017 UK5 is made of porous rock and came in at an angle of 45 degrees, it would start to break into pieces at an altitude of 41 miles and upon reaching the surface would create a crater 2.2 miles in diameter and 5/8 of a mile deep in sedimentary rock. The results 20 miles away from impact would be that of a 6.4 Richter Scale magnitude Earth quake followed by 176 mph air wind blast which would blow down 90% of the trees and collapse wood frame buildings. Fortunately asteroid hunters have not discovered any object like Carson's discovery with our number on it.