Out-of-the-world discoveries - recent space discoveries of two new planets, A new mass of interstellar matter, and billions of new galaxies

Astronomers announce three stunning space discoveries. Could these findings mean we are not alone in the universe?

Astronomers say they may have found at least half of the universe's "missing mass." Since the 1930s, scientists have been looking for this invisible mass, also called "dark matter," which they say keeps galaxies from flying apart. (By their calculations, all the visible stars don't have enough mass, and therefore gravitational pull, to hold galaxies together.)

How did astronomers find this dark matter? They detected increases in the brightness of stars in a nearby galaxy. This brightening, they say, could only be caused by large objects passing in front of the stars. The objects' mass indicates that they are white dwarfs, or burned-out stars. If enough of these dead stars exist in space, they could make up half of the universe's missing mass. What about the other half? Scientists are still looking.

TWO NEW PLANETS

Those who hope to find life elsewhere in the universe have a couple of new places to look: two larger-than-Jupiter planets just discovered orbiting faraway stars. Astronomers detected variations in the light coming from each star, which could be caused by a large planet in orbit. The stars, very similar to the Sun, are about 35 light-years away. (A light-year is the distance light travels in one year, about 9.5 trillion kilometers.)

Based on the stars' brightness and their estimated distances from their planets, scientists think both planets may be warm enough for water to exist there. Since water is essential to life on Earth, the discovery prompts the question: Could these new planets harbor life? Stay tuned as scientists search for signs!

BILLIONS OF NEW

GALAXIES

New photos from the Hubble Space Telescope reveal that the universe may be a lot more crowded than scientists once thought. The photos, like this one, reveal some 1,500 galaxies (groups of stars like our Milky Way) in a tiny speck of space. Based on their view of that speck, scientists now estimate there may be 50 billion galaxies in the universe - 5 times their previous estimate. With 50 to 100 billion stars in each galaxy, the universe may contain 5,000,000,000,000,000,000,000 stars - or about one trillion stars for every person on Earth!