Fuzzy, spread out, asteroid images due to atmospheric and or equipment produced distortions can cause important objects to slip through an asteroid hunter's discovery images undetected. A careful monitoring of the temperature at a number of different locations in the observatory environment and using fans and other techniques to minimize temperature differences restores the power of a telescope so that it can detect possible asteroid threats to planet Earth.
There are likely to be hundreds smaller than softball sized and perhaps several dozen football to beachball sized, natural Earth mini moons, which are so small and fast moving that they are able to slip through asteroid hunters images without being detected.
It has been 20 years since the world woke up to the news that a half mile diameter asteroid, 1997 XF11, discovered by Space Watch on Kitt Peak, had a slight chance of impacting the Earth in 2028. The NASA and JPL's Center for Near Earth Object Studies or CNEOS (see-neos) for short maps space rocks orbits, predicts when they will come close to us, and reliably determines each one's chance of impacting Earth.
Imagine a spacecraft traveling at a speed that would take it from New York to Tokyo in less than a minute, a mere 4 million miles from the surface of our Sun, where it would be exposed to about 500 times the solar radiation we receive here on Earth. Not science fiction but science fact for the NASA Parker Solar Probe on one of its final laps around our star.
A huge Earth approaching asteroid is discovered right before the 2018 monsoon rains settled into the American Southwest. This weather imposed break from observing provides the opportunity for asteroid hunters to make major equipment upgrades and perform routine maintenance.
Most Astronomers find it hard to believe that given perhaps a trillion planets in the Milky Way alone that our Earth is the only one which hosts living organisms. It is both exciting and terrifying to realize we have no concept of what living forms may exist outside Earth in the Milky Way.
Our Moon is the nearest and most likely place for humans to colonize in the near future. It has a hostile environment where air and liquid water as we know them on Earth are not to be found. In the past astronomers hypothesized that comets are the source of water on the Earth and Moon. However, calculations by Svetsov and Shuvalov published in Planetary and Space Science indicate that when a comet impacts the Moon it is likely that 99% of its water evaporates into space and is lost. On the other hand their work indicates that asteroids have been hauling water to our Moon and depositing it in places which are very handy for future human colonists. Specifically it appears probable that 2 to 4.5 % of lunar craters are likely to contain substantial amounts of water in the form of hydrated minerals. These asteroid impact craters are a convenient source of water and solar energy for lunar bases and are likely to be the home of human lunar colonists.
During his last official observing run before retiring, my Catalina Sky Survey teammate, Rik Hill knocked two out of the park. On successive nights he discovered two new potentially hazardous asteroids 2015 TD323 and 2015 TK238. Not to worry, neither of these asteroids are a threat to Earth in the foreseeable future. However, they are large enough and can come close enough to prompt asteroid hunters to keep careful track of them.
The Great Galaxy in Andromeda or M31 as it is also known is one of the furtherest objects that can be seen with the unaided human eye. It is about two and a half million light years away. More than a thousand years ago the a Persian astronomer named Al-Sufi described the Great Galaxy in Andromeda as a "small cloud" in his Book of Fixed Stars. Now there are few places on planet Earth like the Cosmic Campground where one can see it with the naked eye due to inappropriate night time lighting.
Statistically, asteroid hunters are thought to have discovered 90% of our potentially dangerous celestial neighbors greater than 1 KM in diameter. Thus my Catalina Sky Survey teammate Greg Leonard was surprised to discover an unknown very large asteroid moving through the constellation of Persus.
In spite of the shape of the Earth's shadow on the Moon, sailing ships disappearing below the horizon, satellite photographs, orbiting objects, and a mountain of other information about the size and shape of the Earth there are still people who belong a flat Earth Society and even have websites. The number of believers has diminished from 3,500 twenty years ago to less than a few hundred today. Not to worry the Flat Earth Society is being replaced by the Climate Change Deniers.
From the dawn of history, humans have longed to wander amongst the stars. Now we know that comets are able to make such a voyage giving us paths to follow.NASA scientists have suggested that the first interstellar robotic spacecraft could be propelled by a solar sail as large as the state of Texas. Such a mission, perhaps two or three hundred years into the future could follow a comet's path. In this flight of fantasy the spaceship would be inclosed in a reflective spherical heat shield, placed into a Sun grazing orbit, and flung by the Sun's gravity onto a path which will cause it to be ejected from the solar system. After getting to a safe distance from the Sun the robotic spacecraft would deploy its solar sail and use light pressure to accelerate towards its destination. It could be further helped along using a powerful laser projected from the far side of the Moon. In a few decades or maybe even a few centuries it would arrive in a nearby solar system. After that it would be on its own to try to make sense of what is there and to beam information back to its human creators.
My Catalina Sky Survey teammate Greg Leonard knew he had bagged his third comet when he spotted an unknown fuzzy object with a broad tail moving through the constellation of Pisces. Eventually when it looses its volatile materials Comet Leonard will become one of the countless millions of main belt asteroids circling our Sun.
Thirty six hours before my Catalina Sky Survey teammate Rik Hill discovered it, a space rock about size of a Toyota Prius passed about 14,000 miles above the Earth's surface. When Rik first spotted it this small asteroid was about a million miles from us and was moving away from the Earth at 12.6 miles per second. Its orbit had been changed by a narrow escape from the Earth's gravity and it was on a new path around the Sun This small space rock was subsequently observed by telescopes in Russia and Arizona. The Minor Planet Center used these observations to calculate an orbit and give it the name 2015 SK7.2015 SK7 survived it's 2015 encounter with planet Earth. It may not be so lucky the next time.
When the NASA WISE spacecraft ran out of frozen hydrogen, its detectors warmed up, and it was no longer able to conduct its primary mission. It was placed in a hibernation mode and left to orbit the Earth in silence. A couple of years ago NASA engineers figured out that the spacecraft, even with warm detectors, could find some interesting asteroids and decided to wake it up. The WISE spacecraft in turn has produced data on more than15,000 solar system objects including more than 350 Earth approaching asteroids and 60 comets.