A Collection of Celestial Facts: Venus & Mercury

Filled with intense heat and volcanic activity, Venus is considered the sister planet to Earth because it is the same size and showcases similar density and volume. In this article, you will learn more information about this planet, as well as trivia regarding Mercury and the Milky Way.


Despite the similiarities, humans will not be setting shop on the planet Venus anytime soon because of the thick, toxin-filled atmosphere that creates a ‘greenhouse effect’ by trapping heat. The temperatures detected on the planet are hot enough to make lead melt. A unique feature of Venus is that she spins slowly in the opposite direction of most planets. It takes Venus 224.701 days to orbit the Sun. There are no moons associated with Venus.


The swift messenger of the gods lends his name to the planet Mercury, which seems to move quicker than the other planets of our Solar System. With only a slight size advantage over the Sun, Mercury shows the effects of being close to the giant fire star. Mercury is similar to the Moon as it does not have the type of atmosphere that can stop impacts. Because of this, when something crashes into the planet, a crater is left behind. While a Mercury day is very hot because of the Sun, temperatures at night drastically drop hundreds of degrees below freezing. Some of the craters may even be filled with ice. With an orbit shaped like an egg, it takes Mercury 87.969 days to orbit the Sun.

Galaxies and the Milky Way

Comprised of billions of stars held together by the force of gravity, galaxies  possess either a spiral or elliptical shape. If there is one galaxy that you learn about in school, it is the Milky Way , named so for the Greek word for milk. Before telescopes offered enough power to detect the composition of galaxies, they gave off a milky or cloudy appearance. Advancements in technology highlighted the role that individual stars played in creating a galaxy.

Our Solar System is only one of 100 to 200 billion stars in the Milky Way. It measures 100,000 light years in diameter. To complete one orbit around the center of the galaxy, the Sun and all of the planets table about 200,000,000 years.

The brightest galaxy is called the Large Magellanic Cloud. You can only see it in the southern hemisphere. Measuring 39,000 light years in diameter, this galaxy is situated 170,000 light years from Earth. Discovered in 1990, the largest galaxy is called Abell 2029. The nearest galaxy is called the Canis Major Dwarf, which was identified in 1993. It is about 25,000 light years from the Solar System.