“The composition of the Earth-Moon system indicates that the Moon probably formed from a collision between the proto-Earth and a Mars-sized body.
That collision was incredibly violent, and left the Earth hot enough that its atmosphere would primarily consist of vaporized silicate rock.
Once it solidified, those conditions would have left the planet very dry, with our current water largely delivered by smaller bodies that have impacted the Earth since.
So far, only a single type of meteorite has been found to have hydrogen and oxygen isotopes that matched those found in the oceans.
But researchers have now checked a comet derived from the Kuiper belt, and showed that it also is a good match for the Earth’s oceans…
Now, using the ESA’s Herschel observatory, researchers have gotten a good reading on the comet 103P/Hartley 2, which orbits near Jupiter but probably got its start in the Kuiper belt, just outside the orbit of Neptune.
And it turns out that the deuterium/hydrogen ratio is nearly an exact match for that in Earth’s oceans.
That means a large population of comets have just become candidates for seeding our planet with water.”
“In recent years, the idea that the climate is driven by clouds and cosmic rays has received plenty of attention. Interest in the idea was prompted by a Danish physicist named Henrik Svensmark, who first suggested it in the late 1990s.
Using satellite data on cloud coverage, which became available with the establishment of the International Satellite Cloud Climatology Project in 1983, Svensmark found a correlation between lower troposphere cloud cover and the 11-year solar cycle.
He proposed that cosmic rays initiate the formation of aerosols in the lower atmosphere that then form condensation nuclei for cloud droplets, increasing cloud formation from water vapor. Since low-level clouds increase Earth’s albedo (the amount of incoming solar radiation that is reflected back into space), more clouds mean cooler temperatures.
Svensmark claimed that this mechanism was responsible for virtually every climatic event in Earth history, from ice ages to the Faint Young Sun paradox to Snowball Earth to our current warming trend. Needless to say, this would overturn decades of climate research.
Cosmic “rays” are actually energetic subatomic particles. The solar wind shields the Earth from many of the cosmic rays coming from elsewhere in the Milky Way, so the number of rays that reach the Earth is modulated by variations in solar activity, such as the well-known 11-year solar cycle.
Early work by Svensmark and a group at CERN (we recently covered their initial results) has indicated that charged particles like cosmic rays can cause molecules of sulfuric acid, water, or other vapors to combine and form aerosols (particles about 1 nanometer in diameter). This provides a potential link between cosmic rays and cloud formation.”
“The planet Mercury is dotted with holes that appear to be unlike any other landform yet seen in the solar system, new pictures show.
High-resolution photographs from NASA’s MESSENGER spacecraft revealed the shallow, rimless, irregularly shaped depressions—similar to the holes in Swiss cheese—in impact craters all over Mercury.
The features are “widespread both in latitude and longitude,” said study co-author David Blewett, of the Johns Hopkins University Applied Physics Laboratory in Maryland.
Dubbed hollows, the odd landforms can be tens of meters to a few kilometers wide, whereas the impact craters that contain them are tens of kilometers wide or bigger.
The hollows are often seen in clusters on the walls, floors, and peaks of the craters. Many hollows have smooth, flat bottoms and feature highly reflective material.
While Mercury had previously been thought of as a geologically dead planet, with few changes to its surface over the past billion years, “these [hollows] just look fresh,” Blewett added.
“I think there’s a distinct possibility that they’re active today.””
“NASA’s upcoming Technology Demonstration Missions are intended to “transform its space communications, deep space navigation and in-space propulsion capabilities.” Three project proposals have been selected for these missions, which should be launching in 2015 and 2016.
One of those projects, the Laser Communications Relay Demonstration, we’ve told you about already. Another, however, will be demonstrating a mission-capable solar sail.
While NASA has recently tested a solar sail measuring 100 square feet (9.29 square meters), this one will be the largest ever flown, spanning a whopping 15,543 square feet, or 1,444 square meters.
So, what would one do with a solar sail that big?
For one thing, it could be used to gather orbital debris over a period of several years – sort of like a drift net fishing trawler in space.
It could also be included in a satellite’s payload, and activated at the end of the spacecraft’s mission. The sail, still attached to the satellite, could then be used to drag it out of its orbit.”
“Science educator James Drake built this amazing timelapse video from the perspective of the International Space Station as it flew over North and South America.”
“If you could stand on the surface of Kepler-16b, you’d have two shadows.
At sunset, you would see an orange star about the size of the sun and next to it a much fainter red star. As the stars slipped toward the horizon, they would change places in the sky, like partners in a square dance.
You would not need to be Luke Skywalker visiting his home planet of Tatooine in the movie “Star Wars” to watch the twin sunset.
The only science fiction in this story is how to make the 200 light-year journey to Kepler-16, a binary star system jointly sharing the Saturn-sized planet, Kepler-16b…
From a distance about as far as Venus orbits the sun, Kepler-16b circles both its parent stars in 221 days. The stars, which on average have about 21 million miles between them, fly around each other about every 41 days.
The whole system is perfectly aligned to Kepler’s viewing spot, with the bodies crossing paths so that tiny amounts of their radiating starlight regularly, repeatedly and predictably vanish and reappear as the stars and the planet fly past one another.”