In 1937, the small Apollo asteroid Hermes made an unexpected appearance in our solar system. This asteroid, which is estimated to be between 400 and 800 meters in diameter, was first spotted by the German astronomer Karl Reinmuth on October 28th of that year. Its sudden arrival caught many astronomers off guard and sparked a flurry of scientific activity as they scrambled to observe and study this unusual visitor.
What is an Apollo Asteroid?
Before we dive into the specifics of Hermes, let’s first talk about what an Apollo asteroid is. These are a group of asteroids that have orbits that cross Earth’s orbit.
They are named after the first asteroid of this type that was discovered, 1862 Apollo. There are currently over 10,000 known Apollo asteroids, ranging in size from a few meters to several kilometers.
The Discovery of Hermes
As mentioned earlier, Hermes was discovered by Karl Reinmuth in October of 1937 using photographic plates taken at the Heidelberg-Königstuhl State Observatory in Germany. At the time, it was classified as a new planet because its orbit was not initially recognized as being an asteroidal one.
However, as more observations were made and its trajectory was plotted out, it became clear that Hermes was indeed an asteroid and not a planet. In fact, it was the first asteroid to be discovered using modern photographic techniques.
Hermes’ Close Approach
One of the reasons why Hermes caused such excitement among astronomers is because it came very close to Earth during its flyby. On October 30th, just two days after its discovery, it passed within approximately 800,000 kilometers (500,000 miles) of our planet. To put that into perspective, that’s just over twice the distance between the Earth and Moon.
While this may sound like a safe distance, it’s actually quite close in astronomical terms. For reference, the closest approach of any asteroid to Earth in modern history was in 2029, when asteroid Apophis will pass within just 31,000 kilometers (19,000 miles) of our planet.
Studying Hermes
Despite its close approach to Earth, studying Hermes was no easy task for astronomers. At the time of its discovery, it was moving very quickly across the sky and was only visible for a short period each night. Additionally, it was quite faint and difficult to observe with the technology available at the time.
Nevertheless, scientists were able to gather some valuable information about this asteroid during its brief visit. They were able to determine its size and shape by observing how it reflected sunlight, and they also calculated its orbit around the Sun.
Interestingly, Hermes’ orbit is highly eccentric, meaning that it is much more elongated than most asteroids’ orbits. It takes Hermes about 2.1 years to complete one orbit around the Sun and during this time it can come as close as 0.4 astronomical units (AU) to the Sun (closer than Mercury) and as far as 1.7 AU from the Sun.
Conclusion
In conclusion, the small Apollo asteroid Hermes caused quite a stir among astronomers when it made an unexpected appearance in our solar system in 1937. Its close approach to Earth and unusual orbital characteristics made it a fascinating subject of study for scientists at the time.
While we have learned a lot about asteroids since then, Hermes remains an important piece of astronomical history as one of the first asteroids discovered using modern photographic techniques. Its visit serves as a reminder that there is still much we have yet to learn about our solar system and the objects that inhabit it.
- Key Takeaways:
- Apollo asteroids are a group of asteroids that have orbits that cross Earth’s orbit.
- Hermes was discovered in 1937 by Karl Reinmuth using photographic plates taken at the Heidelberg-Königstuhl State Observatory in Germany.
- Hermes passed within approximately 800,000 kilometers (500,000 miles) of Earth during its flyby in 1937.
- Despite its close approach, studying Hermes was difficult due to its faintness and fast movement across the sky.
- Hermes’ orbit is highly eccentric and it takes about 2.1 years to complete one orbit around the Sun.