The mass of the Milky Way Galaxy is a question that has long puzzled astronomers and astrophysicists. Estimates ranged from between 500 billion to three trillion times the mass of our Sun. A new study looked at globular clusters, groupings of a million or so stars surrounding the Milky Way. By measuring the velocity at which they circled our galaxy, as measured by the Hubble Space Telescope and the Gaia Telescope, astronomers determined the Milky Way has a mass around one-and-a-half trillion times as great as our Sun.Read More Hubble and Gaia Team Up to Measure the Mass of the Milky Way
Astronomers have long theorized that planetary systems can be affected by stars passing near solar systems. However, direct evidence of this has never been seen, until now.
Sitting 300 light years from Earth, the star HD 106906 is accompanied by a planet 11 times the size of Jupiter, orbiting the pair of binary stars 738 times further away than the distance between the Earth and the Sun. Computer simulations show that roughly 12 million years ago, another pair of stars passed the system, altering the orbit of this giant world, pulling it far from its stellar companions. Had the encounter not taken place, this world would have crashed into the stars around which it orbits.
Hippocamp is one of the smallest, and darkest, moons of Neptune. Known to astronomers as “The Moon that Shouldn’t be There,” it orbits the giant planet at a distance so close to the larger moon of Proteus that it should have already been destroyed. Researchers using the Hubble Space Telescope have now concluded that this tiny satellite, just 20 miles in diameter, broke off of its larger neighbor billions of years ago, following an impact with a comet. When Voyager 2 visited Neptune in 1989, it photographed a massive impact crater on Proteus, which is likely evidence of this ancient collision.Read More Hubble Reveals Origins of Hippocamp — The Tiny Moon of Neptune that Shouldn’t Be There
Astronomers using the Hubble Space Telescope accidentally found a previously-unknown galaxy, 28 million light years from Earth. This family of stars was found while researchers photographed the globular star cluster NGC 6752. Dubbed Bedin 1, this small, dim galaxy is believed to be around 13 billion years old, leading astronomers to describe it as a “living fossil” of the ancient Universe.Read More Hubble Discovers Dwarf Galaxy Playing ‘Where’s Waldo’ in Our Own Backyard