New research identifies an unexpected source for some of earth's water.
- A lot of Earth's water is asteroidal in origin, but some of it may come from dissolved solar nebula gas.
- Our planet hides majority of its water inside: two oceans in the mantle and 4–5 in the core.
- New reason to suspect that water is abundant throughout the universe.
Our friendly neighborhood gas giant serves as a cosmic catcher's mitt.
- In 1994, a comet struck Jupiter, exploding on the gas giant's surface in an incredibly violent fireball.
- Such collisions are not uncommon for Jupiter. What is uncommon, however, are solar systems with planets like Jupiter.
- Without Jupiter, life on Earth might have been obliterated by comets and asteroids before it even got a chance to begin. The fact that Jupiter-like planets are so rare might be one of the reasons why we haven't found intelligent life yet.
It's an asteroid, it's a comet, it's actually a spacecraft?
- 'Oumuamua is an oddly shaped, puzzling celestial object because it doesn't act like anything naturally occurring.
- The issue? The unexpected way it accelerated near the Sun. Is this our first sign of extraterrestrials?
- It's pronounced: oh MOO-uh MOO-uh.
This meteorite is the oldest known volcanic rock in the solar system, dated at 4,565,000,000 years old.
- It's very rare that we discover something on our planet that was around before we were even a small speck. But every once in a while, we do—and this meteorite is a living testament.
- Scientists estimate the new discovery to be approximately 4.6 billion years old, almost as old as the solar system itself.
- New discoveries like this one bring us a small step closer in piecing together what an earlier version of Earth might have looked like.
Also known as the "Halloween Comet," a 2,000-foot-wide asteroid is expected to pass Earth on November 11.
- The asteroid, named 2015 TB145, made its last flyby on October 31, 2015.
- Some scientists think the asteroid is a dead comet.
- Astronomers say there's no chance it'll collide with Earth, though it'll make a closer approach in 2088.
An asteroid that resembles a human skull will fly past Earth after Halloween this year.
The asteroid — whose nicknames include "Death Comet" and "Great Pumpkin," among others — was first discovered in October 2015 by astronomers using the Pan-STARRS1 telescope in Hawaii shortly before it flew past Earth on October 31, 2015.
During that pass, the asteroid, officially called 2015 TB145, came nearly 300,000 miles away from Earth, which is about 60,000 miles farther than the moon's orbit. NASA wrote at the time that the passing marked "the closest currently known approach by an object this large until asteroid 1999 AN10, at about 2,600 feet (800 meters) in size, approaches at about 1 lunar distance (238,000 miles from Earth) in August 2027."
A farther flyby
On November 11, 2018, the Death Comet is expected to pass Earth at the much farther distance of 24 million miles away. But with a diameter of just 2,000 feet, it'll be too small and distance to see with the naked eye.
Some scientists think the asteroid, which passes Earth every 3.04 years, could be a dead comet. That is, its volatiles may have been stripped over time from the heat of the sun.
"We found that the object reflects about six percent of the light it receives from the sun," Vishnu Reddy, a research scientist at the Planetary Science Institute, said in a 2015 news release. "That is similar to fresh asphalt, and while here on Earth we think that is pretty dark, it is brighter than a typical comet which reflects only three to five percent of the light. That suggests it could be cometary in origin ― but as there is no coma evident, the conclusion is it is a dead comet."
Although the Death Comet is classified as potentially hazardous, astronomers say there's no chance it'll collide with Earth. In 2088, the Death Comet is expected to make another (relatively) close flyby at a distance of 5.4 million miles.
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