Science Daily: Comets and Asteroids

This is a test: Asteroid tracking network observes close approach

On Oct. 12 EDT (Oct. 11 PDT), a small asteroid designated 2012 TC4 will safely pass by Earth at a distance of approximately 26,000 miles (42,000 kilometers). This is a little over one tenth the distance to the Moon and just above the orbital altitude of communications satellites. This encounter with TC4 is being used by asteroid trackers around the world to test their ability to operate as a coordinated international asteroid warning network.

Giant exoplanet hunters: Look for debris disks

There's no map showing all the billions of exoplanets hiding in our galaxy -- they're so distant and faint compared to their stars, it's hard to find them. Now, astronomers hunting for new worlds have established a possible signpost for giant exoplanets.

Remote sensing for cosmic dust and other celestial bodies

Astronomers review the state-of-the-art in polarimetry studies of the small bodies in our solar system. Combined with different observational techniques, polarimetry may be used as a remote sensing technique to measure asteroids' size, to reveal the composition and size variation of dust in comets or of aerosols in planetary atmospheres, or even to detect extra-terrestrial biomarkers.

Ancient asteroid impact exposes the moon's interior

A large basin on the moon has revealed that its interior is made of a different mineral than Earth's interior, contradicting the theory that the interior of the planets look mostly the same.

Mars study yields clues to possible cradle of life

The discovery of evidence for ancient sea-floor hydrothermal deposits on Mars identifies an area on the planet that may offer clues about the origin of life on Earth. The research offers evidence that these deposits were formed by heated water from a volcanically active part of the planet's crust entering the bottom of a large sea long ago.

New telescope attachment allows ground-based observations of new worlds

A new, low-cost attachment to telescopes allows previously unachievable precision in ground-based observations of planets beyond our solar system. With it, ground-based telescopes can produce measurements of light intensity that rival the highest quality photometric observations from space.

Mars' moon Phobos examined in a different light

NASA's longest-lived mission to Mars has gained its first look at the Martian moon Phobos, pursuing a deeper understanding by examining it in infrared wavelengths.

Milky Way's 'most-mysterious star' continues to confound

In 2015, a star called KIC 8462852 caused quite a stir in and beyond the astronomy community due to a series of rapid, unexplained dimming events. The latest findings from astronomers take a longer look at the star, going back to 2006 -- before its strange behavior was detected by Kepler.

The super-Earth that came home for dinner

It might be lingering bashfully on the icy outer edges of our solar system, hiding in the dark, but subtly pulling strings behind the scenes: stretching out the orbits of distant bodies, perhaps even tilting the entire solar system to one side. It is a possible "Planet Nine" -- a world perhaps 10 times the mass of Earth and 20 times farther from the sun than Neptune.

Extreme magnetic storm: Red aurora over Kyoto in 1770

Researchers used historic accounts of a rare red aurora over Kyoto, Japan, in the 18th century to support calculations of the strength of the associated magnetic storm. The September 1770 storm could be 3-10% stronger than the September 1859 storm, the greatest storm in the past 200 years. The research provides insights that could assist preparation for an unlikely, but possible, future intense magnetic storm.

Meteorite tells us that Mars had a dense atmosphere 4 billion years ago

Exploration missions have suggested that Mars once had a warm climate, which sustained oceans on its surface. To keep Mars warm requires a dense atmosphere with a sufficient greenhouse effect, while the present-day Mars has a thin atmosphere whose surface pressure is only 0.006 bar, resulting in the cold climate it has today. It has been a big mystery as to when and how Mars lost its dense atmosphere.

ALMA and Rosetta detect Freon-40 in space

Observations made with the Atacama Large Millimeter/submillimeter Array (ALMA) and ESA's Rosetta mission, have revealed the presence of the organohalogen Freon-40 in gas around both an infant star and a comet. Organohalogens are formed by organic processes on Earth, but this is the first ever detection of them in interstellar space. This discovery suggests that organohalogens may not be as good markers of life as had been hoped, but that they may be significant components of the material from which planets form.

Farthest active inbound comet yet seen

NASA's Hubble Space Telescope has photographed the farthest active inbound comet ever seen, at a whopping distance of 1.5 billion miles from the Sun (beyond Saturn's orbit). Slightly warmed by the remote Sun, it has already begun to develop an 80,000-mile-wide fuzzy cloud of dust, called a coma, enveloping a tiny, solid nucleus of frozen gas and dust. These observations represent the earliest signs of activity ever seen from a comet entering the solar system's planetary zone for the first time.

The volatile processes that shaped Earth

Although it is widely understood that Earth was formed gradually, from much smaller bodies, many of the processes involved in shaping our growing planet are less clear. Astronomers have now untangled some of these processes, revealing that the mini-planets added to Earth had previously undergone melting and evaporation. They also address another scientific conundrum: Earth's depletion in many economically important chemical elements.

Total solar eclipse viewed from space

While people across the nation gazed at August's total solar eclipse from Earth, a bread loaf-sized NASA satellite had a front row seat for the astronomical event.

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