This false-color image shows the near-infrared sky as seen by the COBE satellite. The dominant source of light at this wavelength is stars in our galaxy. So, you end up with an image that shows the thin disk and the central bulge of the Milky Way Galaxy. Our Sun lies in the plane of the disk, 28,000 light years from the center which is why the Milky Way disk appears edge-on to us.
Click on image for full size

How far across is the Milky Way?

At a given time how can one locate the center of our galaxy as we orbit the Sun and the Sun orbits the galaxy? Is our solar system moving away from the center of the galaxy? How many years does it take the Sun to orbit the center of the galaxy? Specifically, where in the universe can our solar system be found?

The Sun and our solar system are in the Milky Way galaxy. There are billions of other stars in the Milky Way Galaxy too - it's like a big star city!

Our galaxy is 90,000 light-years across. It is a spiral galaxy, so it has arms that come from the center of the galaxy like a pinwheel. The Sun is located about 28,000 light-years out from the center of the galaxy in the Orion Arm.

Our solar system is moving around the center of the galaxy. But, we don't get any closer or farther from the center of the galaxy. The solar system is moving through space really fast, but it still takes 200 million years for it to go around once!

The center of our galaxy is beyond the constellation Sagittarius. So, if you can find this constellation in the sky, you'll be looking toward the center of our galaxy! Cool!

The Milky Way is part of a set of galaxies known as the Local Group. The Local Group includes other galaxies within 3 million light-years. This Local Group is part of a supercluster, known as the Virgo supercluster. This supercluster has at least 5,000 member galaxies and is roughly 100 million light-years across. Beyond this, we don't know much about our position in the universe.

Last modified July 18, 2001 by Jennifer Bergman.

You might also be interested in:

What are the retrograde motions of planets in the sky?

It depends on which type of motion you are asking about. If you take a birds-eye view from the top of the solar system all the planets orbit around the Sun in a counter-clockwise (or direct) direction....more

How do Astronauts Live in Space?

Have you ever wondered how astronauts live in space? Did you know they do a lot of the same things we do here on Earth? Astronauts eat, exercise and sleep just like we do. However, their food isn't always...more

How far is the Earth from the Sun, the Moon and all the other planets? How far are all of the planets from the Sun? Do you know of a software that tracks the planets in real-time?

There is a really neat internet program called Solar System Live that shows where all of the planets and the Sun are. If you go to that page, you'll see an image similar to the one on the left. Below the...more

Is it really true that man never really walked on the Moon?

The picture of the American Flag (the one put there by the Apollo astronauts) is waving (or straight out) in the wind. How could that be possible if there is no atmosphere on the Moon? Was it some sort...more

How many planets orbit the sun?

I was wondering if there is a new planet? Are there planets (a tenth planet?) after Pluto belonging to our solar system? What are the names of the new planets discovered in the solar system? Are there...more

Did the Big Bang create any black holes? Wouldn't the universe evolve differently if some of the original energy had disappeared in black holes?

When an object has a really high energy, it can form a black hole. This is called a primordial black hole. Primordial black holes were formed near the beginning of the universe. Primordial black holes...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA