Science Daily: Comets and Asteroids

Composition of Earth-size planets in TRAPPIST-1 system

An astrophysics researcher has identified the possible compositions of the seven planets in the TRAPPIST-1 system. Using thousands of numerical simulations to identify the planets stable for millions of years, Quarles concluded that six of the seven planets are consistent with an Earth-like composition. The exception is TRAPPIST-1f, which has a mass of 25 percent water, suggesting that TRAPPIST-1e may be the best candidate for future habitability studies.

High-pressure experiments solve meteorite mystery

With high-pressure experiments at DESY's X-ray light source PETRA III and other facilities, a research team has solved a long standing riddle in the analysis of meteorites from Moon and Mars. The study can explain why different versions of silica can coexist in meteorites, although they normally require vastly different conditions to form. The results also mean that previous assessments of conditions at which meteorites have been formed have to be carefully re-considered.

Collateral damage from cosmic rays increases cancer risks for Mars astronauts

The cancer risk for a human mission to Mars has effectively doubled following a study predicting a dramatic increase in the disease for astronauts traveling to the red planet or on long-term missions outside the protection of Earth's magnetic field. The new predictive model shows radiation from cosmic rays extends from damaged to otherwise healthy 'bystander' cells.

ALMA returns to Boomerang Nebula

A companion star crashing into a red giant star may explain the chilling power to the Boomerang Nebula.

Hubble 'traps' a vermin galaxy

A new Hubble image shows a distant galaxy as it begins to align with and pass behind a star sitting nearer to us within the Milky Way.

Cold brown dwarf discovered close to our solar system

A new citizen-science tool released earlier this year to help astronomers pinpoint new worlds lurking in the outer reaches of our solar system has already led to a discovery: a brown dwarf a little more than 100 light years away from the Sun. Just six days after the launch of the Backyard Worlds: Planet 9 website, four users alerted the science team to the curious object, whose presence has since been confirmed via telescope.

Rover findings indicate stratified lake on ancient Mars

A long-lasting lake on ancient Mars provided stable environmental conditions that differed significantly from one part of the lake to another, according to a comprehensive look at findings from the first three-and-a-half years of NASA's Curiosity rover mission.

In a cosmic hit-and-run, icy Saturn moon may have flipped

Enceladus -- a large icy, oceanic moon of Saturn -- may have flipped, the possible victim of an out-of-this-world wallop. While combing through data collected by NASA's Cassini mission during flybys of Enceladus, astronomers have found the first evidence that the moon's axis has reoriented, according to new research published in Icarus.

Frost on moon's surface: New evidence

Scientists using data from NASA's Lunar Reconnaissance Orbiter have identified bright areas in craters near the moon's south pole that are cold enough to have frost present on the surface.

Juno mission to Jupiter delivers first science results

NASA's Juno mission is rewriting what scientists thought they knew about Jupiter specifically, and gas giants in general, according to a pair of Science papers released today. The Juno spacecraft has been in orbit around Jupiter since July 2016, passing within 3,000 miles of the equatorial cloudtops.

How radioactive decay could support extraterrestrial life

In the icy bodies around our solar system, radiation emitted from rocky cores could break up water molecules and support hydrogen-eating microbes. To address this cosmic possibility, a team modeled a natural water-cracking process called radiolysis. They then applied the model to several worlds with known or suspected interior oceans, including Saturn's moon Enceladus, Jupiter's moon Europa, Pluto and its moon Charon, as well as the dwarf planet Ceres.