The Moon and Beyond
Professor Rodrigo Negreiros discusses the science and mystery, of the Moon.
The Moon is our well-known and cherished celestial neighbor, perhaps only second to the sun in familiarity. This small planetary body continually orbits our planet and has been a companion to humanity since the dawn of history, inspiring numerous myths, stories, and romantic tales.
In addition to its role as a muse for art and literature, the moon has always sparked intense scientific curiosity, as it holds many secrets that could be crucial for understanding the solar system and specifically the formation of Earth.
Even today there is great scientific debate regarding the origins of the moon, with many theories proposed. The most accepted model is that a Mars-sized planet collided with Earth in its early stages of formation, resulting in a debris ring that eventually coalesced into what is the moon. There is much evidence that supports this scenario, although as of today it cannot be unequivocally proven – as is often the case in sciences. This planet that may have collided with Earth has been named by scientists, quite appropriately, Theia, who is a Titan in Greek mythology, mother of Selene, the goddess of the Moon. Interestingly, according to the Theia hypothesis, the collision with Earth is probably responsible for the angular tilt our planet experiences to this day, which is responsible for our seasons. So, beside the tides, we may have the Moon to thank for our seasons!
Image of the Moon taken by Prof. Negreiros with the telescope on CatholicTech’s campus
Earth is somewhat unique in the solar system for having just one natural satellite – the Moon – whereas most planets are accompanied by numerous moons. For example, Jupiter boasts over 95 confirmed moons, and Saturn has more than 140! It’s worth noting that inner planets generally have fewer natural satellites due to their smaller masses, but even Mars, our nearest neighbor, has two moons.
Remarkably, Earth occasionally finds itself with a temporary second moon. This event takes place when an asteroid from the Arjuna asteroid belt comes sufficiently close to be captured by Earth’s gravitational pull. Although the Arjuna belt is less well-known than the main asteroid belt located between Mars and Jupiter, it contains numerous asteroids in orbits near Earth around the Sun.
Occasionally, an asteroid from the Arjuna belt ventures close enough to Earth to become ensnared by its gravity, beginning to orbit the planet as a secondary moon. However, this is only a transient occurrence, as the gravitational pull is typically not strong enough to maintain the capture. After spending a brief period as a second moon, these objects usually escape Earth’s grasp and proceed on their paths through the solar system, often gravitating towards the Sun.
Currently, we are experiencing a period where Earth officially has two moons. As of September 29th, 2024, Earth has been orbited by a second moon named 2024 PTS, which will continue circling our planet until the end of November before moving on towards its final destination, leaving Earth with just one Moon again.
Regrettably, temporary moons like 2024 PTS are too small and faint to be seen in the night sky or even with binoculars and home telescopes. Observing these objects requires large professional telescopes and digital techniques that enable scientists to detect objects with low brightness.
Luckily, our cherished Moon is always visible in its full glory, letting us marvel at the universe that gives our planet two moons, even if briefly. Enjoy these pictures of our beloved Moon taken by the CatholicTech Telescope!