An Air Force satellite carrying instruments to measure wind velocity on Earth and another to measure disturbances in the solar wind also detected explosive stars, or "novae." These novae are stellar flare-ups that are not as catastrophic or bright as supernovae. The observations were of confirmed novae, but some of the data captured the explosion before it achieved peak brightness. This has not been done before from the ground or space. Such observations can be used to study the phenomena that create such repeated stellar explosions in greater detail.
A huge, mountainous ridge circling the equator of Saturn's moon Iapetus was discovered in 2004 by the Cassini spacecraft. The ridge reaches 12 miles high and runs 1,000 miles (1,600 km) from end to end. Astronomers now propose a new idea for its formation.
A NASA telescope has detected a previously unseen structure centered in our Milky Way galaxy. It's pair of gamma-ray emitting bubbles, 50,000 light years across, that could be a remnant of an eruption from the black hole at the galaxy's center.
The EPOXI Deep Impact comet investigation team, known for its flyby of Comet Tempel 1, was able to re-use its spacecraft to fly near a second comet, Hartley 2. The second flyby was executed in November 2010. The close approach of the spacecraft showed the comet's unusual shape, and jets emerging from various lumps. The images are now being analyzed to glean clues to the formation of Hartley 2.
Elliptical galaxies are traditionally thought of as old objects where most star formation happened long ago and then evened out. They appear smooth and more or less featureless. However, Hubble observations reveal that elliptical galaxies may not be so undisturbed. These objects, judging by a galaxy called NGC 4150, may actually cannibalize smaller galaxies. In doing so, they become the sites of localized star formation, though less than in spiral galaxies.
A total eclipse of the Moon took place in the morning hours of December 21. Eclipses of the Moon only happen when the Moon is full, and it passes through the shadow cast by our planet. This eclipse was visible for all of North America.
Scientists recently discovered water ice on an asteroid for the second time in a few months. This new finding suggests that water is more common on asteroids than previously thought. Perhaps asteroids delivered much of the water present on the early Earth.
A new proposal suggests that Saturn's rings may have come from a planet-size collision. A moon the size of Mercury may have smashed into Saturn to create its spectacular ring system.
Hubble spies an X-shaped object streaking through space -- and learns what created it. And the Dawn spacecraft is zeroing in on the asteroid Vesta. Learn how Hubble is helping it get there.
The universe began with a hot explosion called the Big Bang. The aftermath of the Big Bang consisted mostly of radiation, but as things cooled, the elements hydrogen and helium formed. Hubble's new Cosmic Origins Spectrograph is giving us information about the early formation process, including the development of galaxies and the "re-ionization" of the universe.
The giant elliptical galaxy, M87, has a supermassive black hole in its center. A long jet extends outward from the core of the galaxy, and huge radio lobes reach into space. New X-ray and radio data from the Chandra X-Ray Observatory and the Very Large Array Radio Observatory show that eruptions from the core of M87 have long-range effects. The hot eruptions stop cool gas from falling toward M87?s center to form new stars, and even affect surrounding galaxies.
A celestial event recorded by the ancient Greeks may be the earliest sighting of Halley's Comet, which would push accounts of Halley back 226 years. According to ancient writers, a large meteorite smacked into northern Greece between 466 B.C. and 467 B.C. -? but the writers also describe a comet in sky at time that the meteorite fell to Earth.
The origin of the two moons of Mars -? Phobos and Deimos -? has been a long-standing puzzle. Now, new evidence indicates that Mars' largest moon, Phobos, is made from rocks blasted off Martian surface in a catastrophic event. Astronomers have speculated that both moons could be asteroids that were captured by Mars's gravity, but the latest evidence supports another, more violent possibility.
The Lunar Reconnaissance Observer has mapped the surface of the Moon. Researchers have examined the imagery and cataloged multitudes of craters on the surface. Interested members of the public, known as citizen scientists, can participate in the cataloging. Participants have found interesting craters, bridge arches, and lava tube "skylights" through the Moon Zoo program.
The material left in the outer part of the solar system can contain clues to the formation and early stages of the Sun and its planets. A plethora of rocky objects, comets and possibly dwarf planets reside in our solar system well beyond the orbit of Neptune. Most are small, dark objects that are very hard to find because they reflect so little light. Using the Hubble archive, a team searched some of the images and found new distant solar system objects. They range in size and suggest a fair number of collisions have occurred throughout the 4.5 billion year lifetime of the Sun.
A recently discovered "monster star" could once have been 320 times as massive as the Sun and 10 million times as bright -? twice as massive as scientists thought a star could be. This monstrous star resides deep inside the Tarantula Nebula, a bright region of hydrogen gas in the neighboring galaxy known as the Large Magellanic Cloud.
Researchers have identified rocks they say could contain fossilized remains of life from early Mars. The team made the discovery in a region known as Nili Fossae. The trench on Mars resembles an area in Australia where some of the earliest fossil evidence of life on Earth was found.
Knocked aside by a black hole, a star is hurtling out of our galaxy at tremendous speed. Hubble is searching the realm beyond Neptune for the icy bodies that give birth to comets.
Dark energy, a mysterious force that seems to be accelerating the expansion of the universe, was discovered in 1998. Ever since, astronomers have been trying to refine the measurements of the effects of dark energy, and figure out exactly what it is. Observations of supernovae, cosmic microwave background radiation, and other phenomena have contributed to the trove of data about dark energy. The latest method to refine the measurements relies on studying the dark matter distribution of a huge cluster of galaxies known as Abell 1689.
Every decade, the National Academy of Sciences convenes a committee of astronomers to survey the science community and prioritize research questions and facilities for the next decade. Funding is tight and astronomers' ambitions are grand, so information gathering is vital. The results are presented in the Astro 2010 report. The recommendations of the committee attempt to produce a balanced program of space- and ground-based astronomy, driven by the pressing astrophysics questions of the day.