Our Nearest Neighbors

Technology is allowing humans to see further than ever before but to date we still know so little even about Earth’s closest neighbors. 

Planet Earth only has 1 moon, unusual for our Solar System. The fifth largest moon in the Solar System, it was formed 4.5 billion years ago, shortly after the formation of Earth. The Moon orbits just under 240,000 miles away from Earth.

For thousands of years humans have imagined pictures in the stars, including animals like bears and dogs. A group of stars forming a constant pattern is called a constellation. In reality these stars could be millions of miles apart.

Mars is located just under 140 million miles away from Earth. Light coming from Mars would take around 3 minutes to travel and reach Earth. Spacecraft traveling from Earth to Mars spend 9 months in the journey.

Mars Rovers exploration vehicles were designed and launched by the United States. They move around the surface of Mars and use a number of different on–board tools to perform various scientific experiments. Currently 3 rovers are on Mars, however only 2 are operational.

The word “close” is very misleading. Although this is our next nearest solar system, it’s still over 4 light years away. This equals to over 25 trillion miles. It takes 4 Earth years for light from the Alpha Centauri system to reach Earth.

Proxima Centauri is the closest sun outside our Solar System. It’s also a very small sun, just a little larger than Jupiter. Some debate still exists over whether Proxima Centauri is actually part of the Alpha Centauri system or is passing through the system.

Andromeda is 2.5 million light years from Earth. It takes 2.5 million years for the light from this galaxy to reach our atmosphere. The Andromeda Galaxy is the furthest object in the universe you can see with the naked eye.

With the help of X-ray telescopes, astronomers have discovered a number of black holes located within the Andromeda Galaxy. After identifying 26 possible black holes, they determined at least one was a supermassive black hole. 

Although Segue 1 is found quite close to the Milky Way, it takes 75,000 years for its faint light to reach Earth. Astronomers estimate that it orbits the Milky Way once every 600 million years.

Segue 1 seems to contain ancient stars, possibly dating back to when the universe came into existence. This is evidenced by the apparent low metal content of its stars. Metal didn’t appear in the universe until a few generations of stars went into supernova. 

Betelgeuse is a rare type of star called a red supergiant. Its size changes and it can be 700–1,000 times bigger than our Sun. Seen all over the world, it forms part of the constellation known as Orion, the hunter. Betelgeuse is the tenth brightest star in the sky.

If Betelgeuse took the place of our Sun it would reach all the way past the asteroid belt, devouring Mercury, Venus, Earth, Mars, and possibly even Jupiter. It’s approximately 700 times larger than our Sun.