By using galaxies as giant gravitational lenses, an international group of astronomers using the Hubble Space Telescope have made an independent measurement of how fast the Universe is expanding. The newly measured expansion rate for the local Universe is consistent with earlier findings. These are, however, in intriguing disagreement with measurements of the early Universe.
“We’re made of star stuff,” astronomer Carl Sagan famously said. Nuclear reactions that happened in ancient stars generated much of the material that makes up our bodies, our planet and our solar system. When stars explode in violent deaths called supernovae, those newly formed elements escape and spread out in the universe.
Every few thousand years, an unlucky star wanders too close to the black hole at the center of the Milky Way. The black hole’s powerful gravity rips the star apart, sending a long streamer of gas whipping outward. That would seem to be the end of the story, but it’s not. New research shows that not only can the gas gather itself into planet-size objects, but those objects then are flung throughout the galaxy in a game of cosmic “spitball.”
Scientists planning the the next phase of NASA’s New Horizons mission, a robotic craft that completed the first exploration of Pluto in 2015, are going into the flyby of a frozen, faraway city-sized clump of rock on New Year’s Day 2019 armed with little knowledge of the target lurking around 4 billion miles from Earth.
Decisions on the future of a joint robotic mission between NASA and the European Space Agency to demonstrate the ability to deflect an asteroid on a collision course with Earth have been put off until later this year after European governments declined to fully fund their part of the project in December.