Besides being Independence Day, Monday is also the day of aphelion when the Earth is farthest from the sun at 94.5 million miles.
There is a slight bend in the Earth’s orbit from the gravitational interaction with the Moon and, to a lesser extent, the planets, so the exact apogee value changes. Tomorrow it will be 94509.598 miles but next year it will be a little less at 94506364 miles and in 2024 it will be 94,510,539 miles.
The fact that aphelion occurs during summer shows that distance from the sun is not the cause of the seasons. The steeper angle of the sun’s rays hitting our part of the Earth in summer concentrates the sun’s energy, and the longer the sun is above the horizon during summer, means it will be warmer in summer than winter (more power for baking and baking time means it bakes in Bakersfield summer) .
In June, early morning risers had a wonderful view of all the planets with the naked eye in the eastern sky. On June 24, the line-up including the crescent moon beautifully displayed all objects in the same order as their distance from the sun and all roughly evenly spaced.
Monday morning or the next morning will probably be the last time to see all the planets at the same time. They are still displayed in the same order as their distance from the Sun. Mercury is rapidly receding toward the sun, so it will soon be lost in the twilight glow.
The separation of the two extremes, Mercury and Saturn, has increased to the point where they do not fit into the same star chart. The accompanying chart focuses on the easiest-to-see planets: Venus, Mars, Jupiter, and Saturn. The moon in the evening sky is like a crescent moon in the west. It will be in the first quarter (half lit) on Wednesday night and in the full phase on the night of July 13th.
In the news of space exploration, there was a setback for the Psyche mission that will explore the metallic asteroid of the same name. Delays in obtaining the spacecraft’s flight program delayed testing of the systems beyond the launch window of August 1 to October 11. at the asteroid in 2026. The launch windows in 2023 and 2024 will be tracks that don’t include Mars boost, so Psyche won’t arrive until 2029 or 2030.
Asteroid Psyche is about 130 miles wide and is found in the asteroid belt about three times farther from the Sun than Earth. What is unusual about Psyche is that it is composed mostly of the metallic iron and nickel, like the core of our planet. Other asteroids are mostly rocky or icy bodies. Psyche may be the exposed core of a small planet that lost its outer lithosphere and crust from the many violent collisions that struck all solid bodies in the early Solar System. In addition to its scientific value, the mineral world may be an attractive source of materials.
On the plus side, the James Webb Space Telescope is due to release its first images and spectroscopy data on July 12 at 7:30 a.m. PDT. There will be a live press conference with simultaneous release on major social media platforms and on the website nasa.gov/webbfirstimages.
At noon on July 13, web experts will answer questions about the first images and data in NASA’s Science Live presentation on YouTube and Facebook. People can submit questions on Twitter using the hashtag #UnfoldtheUniverse or in the YouTube/Facebook chat sections.
Contributing columnist Nick Strobel is Director of the William M. Thomas Planetarium at Bakersfield College and author of the award-winning website AstronomyNotes.com.
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