Asteroid tagged posts

Craters on the surface of the asteroid 21 Lutetia. Credit: ESA

An international study reveals that asteroids have endured a multitude of impact strikes since their formation 4,565 million years ago. Scientists have reconstructed a timeline of these collisions using a physics-based model which reproduces the process through time, comparing its results with present-day information about chondrite meteorites.

The size distribution of the objects which make up the asteroid belt between Mars and Jupiter indicates that these asteroids have been struck by projectiles >20cm in size at least 100 million times. The resultant craters from these strikes are proportional to both the diameters and the velocities of these projectiles.

The information compiled on ordinary chondrites indicates that these m...

A diagram showing how the meteors will appear to emanate from a radiant in the constellation of Gemini, located in the east in the evening sky. Credit: Greg Smye-Rumsby / Astronomy Now

From 13 to 15 Dec, weather permitting, skywatchers across the world will be looking up as the Geminid meteor shower reaches its peak, in potentially one of the best night sky events of the year. Tens of ‘shooting stars’ or meteors may be visible each hour (the theoretical maximum under ideal conditions is about 120/hr). Meteors are the result of small (mm- to cm-sized) particles entering the Earth’s atmosphere at high speed, burning up and superheating the air around them, which then shines as a characteristic short-lived streak of light...

This is the temperature of the surface around the southern pole of the moon according to LRO data. Credit: NASA

Water reserves found on the moon are the result of asteroids acting as ‘delivery vehicles’ and not of falling comets as was previously thought. Using computer simulation, scientists have discovered that a large asteroid can deliver more water to the lunar surface than the cumulative fall of comets over a billion year period.

At the beginning of the space age, during the days of the Apollo program, scientists believed the moon to be completely dry. At these earliest stages in satellite evolution, the absence of an atmosphere and the influence of solar radiation were thought enough to evaporate all volatile substances into space...