Every 90 minutes the International Space Station (ISS) goes around the Earth. Astronauts on board see 16 sunrises and sunsets every 24 hours. Besides the sun and moon, Venus is the brightest solar system body we can see. It’s spectacular viewed from a dark sky, but even big-city dwellers can spot the planet through the miasma of artificial light. I remember playing hide-and-seek with Venus in downtown Chicago as a teenager.
This photo, taken on May 28 from orbit, shows the twilight arc along the planet’s circumference and even a rosy hint of the impending sunrise. Venus stands a short distance apart from the edge. On the ISS, cosmic views are not affected by Earth’s atmospheric conditions or urban lighting. However, the station’s trajectory, attitude, and structures such as solar panels or visiting spacecraft can hinder a clear line of sight. The same can happen on Earth when trees and buildings get in the way of seeing celestial objects. I have a friend who will cut down trees on his property now and again to either open or re-open some fresh sky.
It’s been nearly a month since that photo, and Venus has drawn closer to the sun. Matter of fact, it’s been creeping ever closer to the eastern horizon, making now your last shot at seeing it at dawn before it’s lost in the solar glare. You’ll need a wide-open view to the east-northeast to spy the spark of Venus only about 3° above the horizon a half-hour before sunrise. That’s quite a challenge so I’d love to know if you can still see it. Bring binoculars to improve your chances.
In asteroid news, NASA’s OSIRIS-REx spacecraft recently descended into the closest orbit ever around the asteroid Bennu, approaching to within 2,231 feet (680 meters) of the surface, about the altitude of a small plane. Not long after the probe arrived at Bennu it photographed rock particles being ejected from its surface. Eager for a closer look, mission control took the spacecraft down to the lower altitude and has been focusing along the asteroid’s horizon searching f. I’ve got to say the pictures of the surface are getting more and more incredible.
Photos taken as the probe has moved down are pretty incredible, the reason I wanted you to see them. It’s almost close enough to get that “standing on the surface” feeling. If you were walking there it would incredibly tricky to navigate with all those boulders. We know that meteorites originate from asteroids. What your looking at are what meteorites look like before they enter Earth’s atmosphere and blacken up from the heat of entry to form a fusion crust.
What I find intriguing about these close-ups are the differences in the color (tone) and texture of the rocks which to my eye would indicate a difference in their compositions. It appears that Bennu isn’t just made up of one kind of material but several types — a stew probably created through earlier impacts and mixing.