As the nights grow longer in early July, we find ourselves looking up at a seemingly empty sky, devoid of the familiar planets that we are used to seeing. Mars, Jupiter, and Saturn have become residents of the dawn, leaving our evenings planet-less for the remainder of 2024.
However, there are two intriguing planets making their appearance low in the western sky at dusk: Mercury and Venus. These inner worlds are slowly returning, and the quest is on to locate them after sunset.
Mercury’s apparition in July is particularly fascinating, offering one of the best opportunities to observe the planet for observers worldwide. This is because Mercury is heading towards aphelion, its farthest point from the Sun, at 0.4667 Astronomical Units (AU) on July 27th, just five days after its greatest elongation. On July 22nd, when Mercury is at its greatest elongation, it will present an 8-inch diameter disk that is 45% illuminated, shining at a respectable magnitude of +0.3.
While Mercury may appear as nothing more than a tiny dot through a telescope, the thrill lies in knowing what you are actually seeing. Unlike the other planets, Mercury’s status as the innermost planet in our solar system means that it always lingers low in the atmosphere’s haze, making it difficult to observe surface details. It wasn’t until space exploration that we gained more knowledge about this mysterious planet. NASA’s Mariner 10 mission in the 1970s provided a glimpse of Mercury’s airless, cratered surface. Subsequent missions, such as NASA’s Mercury MESSENGER and the joint ESA/JAXA BepiColombo, have offered even more detailed information.
In addition to Mercury, Venus is also making its presence known in the evening sky. Although much brighter than Mercury, Venus is currently lower on the horizon. It is slowly catching up to Earth from the farside of the Sun. Think of Venus as a runner trying to catch up with Earth on the inside track of the solar system. Venus will grace our evening skies for the rest of 2024, reaching its greatest eastern elongation from the Sun on January 10th, 2025.
The sky scene becomes even more captivating as the month progresses. On July 6th, Mercury will even transit the Beehive Cluster, also known as Messier 44. Using binoculars, you might also spot the dwarf planet 4 Vesta nearby. Venus will have its own meeting with Messier 44 on July 18th, albeit much closer to the horizon.
If you have never seen Mercury before, now is the perfect time to try and check it off your life list. Join the hunt for the elusive innermost planet and explore the wonders of our celestial neighborhood.
An FAQ section based on the main topics and information presented in the article:
1. Which planets are currently visible in the evening sky?
Currently, two planets, Mercury and Venus, are visible in the evening sky.
2. Why are Mars, Jupiter, and Saturn not visible in the evening sky?
Mars, Jupiter, and Saturn have become residents of the dawn, meaning they are currently only visible in the early morning sky.
3. Why is Mercury’s apparition in July particularly fascinating?
Mercury’s apparition in July is fascinating because it offers one of the best opportunities to observe the planet for observers worldwide. This is because Mercury is heading towards aphelion, its farthest point from the Sun, on July 27th.
4. How can we locate Mercury in the evening sky?
To locate Mercury in the evening sky after sunset, one needs to look towards the western sky. On July 22nd, when Mercury is at its greatest elongation, it will appear as an 8-inch diameter disk that is 45% illuminated.
5. Why is observing Mercury through a telescope thrilling?
Observing Mercury through a telescope may appear as nothing more than a tiny dot, but the thrill lies in knowing what you are actually seeing. Mercury’s status as the innermost planet in our solar system means that its surface details are difficult to observe due to its low position in the atmosphere’s haze.
6. What missions have provided information about Mercury?
NASA’s Mariner 10 mission in the 1970s provided a glimpse of Mercury’s airless, cratered surface. Subsequent missions, such as NASA’s Mercury MESSENGER and the joint ESA/JAXA BepiColombo, have offered even more detailed information.
7. What about Venus in the evening sky?
Venus is also visible in the evening sky. It is currently lower on the horizon but will gradually catch up to Earth. Venus will be visible in the evening skies for the remainder of 2024, reaching its greatest eastern elongation from the Sun on January 10th, 2025.
8. Are there any other interesting celestial events happening?
Yes, on July 6th, Mercury will transit the Beehive Cluster (Messier 44) in the sky. And on July 18th, Venus will have its own meeting with Messier 44.
Definitions:
– Aphelion: The point in a planet’s or comet’s orbit that is farthest from the Sun.
– Astronomical Unit (AU): A unit of length used to measure distances in space, approximately equal to the average distance from the Earth to the Sun.
– Greatest elongation: The point in a planet’s orbit where it appears farthest from the Sun as seen from Earth.
Suggested related links:
– NASA’s Mercury Overview
– NASA’s Venus Overview