Science Daily: Comets and Asteroids

Dawn of a galactic collision

A riot of color and light dances through this peculiarly shaped galaxy, NGC 5256. Its smoke-like plumes are flung out in all directions and the bright core illuminates the chaotic regions of gas and dust swirling through the galaxy's center. Its odd structure is due to the fact that this is not one galaxy, but two -- in the process of a galactic collision.

Life's building blocks observed in spacelike environment

Where do the molecules required for life originate? It may be that small organic molecules first appeared on earth and were later combined into larger molecules, such as proteins and carbohydrates. But a second possibility is that they originated in space, possibly within our solar system. A new study shows that a number of small organic molecules can form in a cold, spacelike environment full of radiation.

Cold suns, warm exoplanets and methane blankets

Three million years ago, the sun shone weaker, but Earth stayed surprisingly warm. Carl Sagan thought a greenhouse effect must have been to thank. A model built on 359 chemical processes has finally arrived at scenarios with a reasonable chance of producing the needed methane on ancient Earth. The model has broad parameters in hope that it may someday be of use to interpret conditions on exoplanets.

Why meteroids explode before they reach Earth

When a meteor comes hurtling toward Earth, the high-pressure air in front of it seeps into its pores and cracks, pushing the body of the meteor apart and causing it to explode, report scientists.

Mars' atmosphere well protected from the solar wind

Despite the absence of a global Earth-like magnetic dipole, the Martian atmosphere is well protected from the effects of the solar wind on ion escape from the planet. New research shows this using measurements from the Swedish particle instrument ASPERA-3 on the Mars Express spacecraft.

NASA telescope studies quirky comet 45P

When comet 45P zipped past Earth early in 2017, researchers observing from NASA's Infrared Telescope Facility, or IRTF, in Hawai'i gave the long-time trekker a thorough astronomical checkup. The results help fill in crucial details about ices in Jupiter-family comets and reveal that quirky 45P doesn't quite match any comet studied so far.

Two Super-Earths around red dwarf K2-18

New research has revealed that a little-known exoplanet called K2-18b could well be a scaled-up version of Earth. Just as exciting, the same researchers also discovered for the first time that the planet has a neighbor.

The bacterial community on the International Space Station resembles homes

Microbiologists have analyzed swabs taken by astronauts on the International Space Station (ISS) and compared them with samples from homes on earth as well as the Human Microbiome Project. This work, part of a nationwide citizen science project called Project MERCCURI, found that the microbial community in this unique habitat was very diverse and more closely resembled that of homes than of humans.

Trickle-down is the solution (to the planetary core formation problem)

Scientists have long pondered how rocky bodies in the solar system -- including our own Earth -- got their metal cores. According to new research, evidence points to the downwards percolation of molten metal toward the center of the planet through tiny channels between grains of rock.

Bronze Age artifacts used meteoric iron

Though meteorites had already been recognized as one source of iron objects, the scientific community couldn't determine whether they accounted for most or simply a few Bronze Age iron artifacts. Scientists have now demonstrated that iron used during the Bronze Age is always meteoric and he explained how this practice was abandoned during the Iron Age.

All missions on board for NASA heliophysics research

Scientists have been studying the near-Earth environment for the better part of a century, but many mysteries -- like where the energetic particles that pervade the area originate and become energized -- still remain. In a new type of collaborative study, scientists combined data from 16 separate NASA and Los Alamos National Laboratory spacecraft to understand how a particle phenomenon in the magnetic environment around Earth occurs. These events, called substorms, can cause auroras, disrupt GPS communications and, at their most intense, damage power grids.

How the Earth stops high-energy neutrinos in their tracks

For the first time, a science experiment has measured Earth's ability to absorb neutrinos -- the smaller-than-an-atom particles that zoom throughout space and through us by the trillions every second at nearly the speed of light. The experiment was achieved with the IceCube detector, an array of 5,160 basketball-sized sensors frozen deep within a cubic kilometer of very clear ice near the South Pole.

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