The Milky Way is considerably larger than previously thought—15 percent larger. But more importantly, astronomers discovered it’s 50 percent denser in mass, which is like weight. Andromeda was previously thought to be the larger, dominant galaxy and the Milky Way a smaller version of it. Now they believe the two galaxies to be equal in size resulting in the gravity between the Milky Way and Andromeda to be stronger. What that may mean is that the Milky Way could be crashing violently into Andromeda sooner than predicted—still 2 to 3 billion years from now fortunately.
Reid and his colleagues measured the brightest newborn stars in the Milky Way at different times in Earth’s orbit around the Sun mapping not just their locations, but also in the third dimension of time. The speed at which the spiral-shaped Milky Way is spinning around its center was then determined. How fast is our galaxy spinning? 568,000 miles per hour–scientists previously thought it was 492,000 mph. Once the speed of the galaxy’s spin was determined, complex formulas then determined the mass of all of the dark matter in the Milky Way. The dark matter, all of the “stuff” we can’t see, is by far the heaviest stuff in the universe. The conclusion is that the Milky Way is around one-and-a-half times the mass previously calculated and accepted by astronomers.
- There are around 100 billion stars in the Milky Way.
- Our galaxy belongs to a cluster of at least 30 galaxies called the Local Group.
- The Milky Way is a younger, spiral galaxy. Older and bigger galaxies are called ellipticals and look like a giant ball.
- The nearest star to our Sun is the Proxima Centauri, a member of the Alpha Centauri triple star system. Light takes 4.22 years to reach us from Proxima Centauri.
- The Earth orbits around the Sun at 60,000 miles per hour.
- The Sun moves around the Milky Way at 140 miles per second.
Now you’re a little smarter, Girlfriend — And so am I.