Distance to Stars

Our galaxy is a big place, with hundreds of billions of stars. Some stars are relatively close and others are over on the other side of the galaxy. Let’s take a look at the distance to stars, just to put your daily commute in perspective.

The closest star to Earth is the Sun, of course. It’s located about 150 million km away. Light alone takes 8 minutes to travel from the Sun to the Earth. If you were to make a road trip to the Sun, traveling at an average speed of 120 km/hour, it would take you about 1.25 million hours to drive there; that’s 143 years. Spacecraft travel much quicker. The fastest spacecraft ever launched from Earth is NASA’s New Horizons spacecraft, currently making its way towards Pluto at a speed of 70,000 km/hour. It could make the trip to the Sun in about 90 days. It’s going to take New Horizons more than 10 years to reach Pluto, which is located about 6 billion km from Earth.

Okay, so now you have a good point of comparison. The nearest star to the Sun is Proxima Centauri, located about 4.2 light years away. In other words, light alone takes 4.2 years to make the 40 trillion km journey to Proxima Centauri, not to mention what a spaceship would need to take. Moving at its current speed of 70,000 km/h, New Horizons would need about 65,000 years to reach the nearest star.

And Proxima Centauri is a really close star! According to Phil Plait, the most distant star you can see without a telescope is Mu Cephei; a red supergiant star with 1,500 times the diameter of the Sun. It’s about 5,000 light years away.

The center of the Milky Way is about 26,000 light years away, and the nearest large galaxy (which you can see with the unaided eye) is Andromeda, located about 2.5 million light years.

The distances to stars in space is vast. Even the closest stars would take thousands of human lifetimes to reach with current technology.

We have written many articles about stars here on Universe Today. Here’s an article about the closest star to Earth, and an article about how long it would take to travel to the closest star.

Want more information on stars? Here’s Hubblesite’s News Releases about Stars, and more information from NASA’s imagine the Universe.

We have recorded several episodes of Astronomy Cast about stars. Here are two that you might find helpful: Episode 12: Where Do Baby Stars Come From, and Episode 13: Where Do Stars Go When they Die?

References:
http://ds9.ssl.berkeley.edu/solarweek/WEDNESDAY/wed_spaceweather.html
http://www.astro.wisc.edu/~dolan/constellations/extra/nearest.html
http://imagine.gsfc.nasa.gov/docs/features/objects/milkyway1.html