Dark matter makes up 90% of the matter in both systems, the study finds.
A misty forest path … Where does it lead? Tommy Richardsen captured this image in Sørkjosen, Troms, Northern Norway.
After the waxing crescent moon sets at late evening on Wednesday, look for one of summer’s most beautiful celestial sights. Be sure you are looking in a dark country sky, far away from the the glare of city lights. You’ll find a hazy pathway stretched across the sky. This band is the starlit trail of our own Milky Way galaxy. We in the N. Hemisphere look southward in late in the evening – toward the richest part of the Milky Way – to find a very small constellation called Scutum the Shield.
Using data from NASA’s Cassini spacecraft – which has been orbiting Saturn, weaving among its moons, since 2004 – scientists have now mapped 101 distinct geysers erupting from the surface of Enceladus, an ice world and arguably Saturn’s most fascinating moon. They’ve concluded that the only plausible source for the geysers is an underground sea now known to exist beneath Enceladus’ icy surface.
An international team of scientists cautions that the loss and decline of animals is contributing to what appears to be the early days of the planet’s sixth mass biological extinction event.
Since 1500, more than 320 terrestrial vertebrates have become extinct. Populations of the remaining species show a 25 percent average decline in abundance. The situation is similarly dire for invertebrate animal life.
The chart above provides a comparison of the distances driven by various wheeled vehicles on the surface of Mars and Earth’s moon. On July 27, the Opportunity rover passed 25 miles driven – an off-world driving distance record. Opportunity has gone farther than any other earthly wheeled vehicle on another world. It’s especially remarkable, NASA says, because Opportunity was intended to drive about one kilometer (.6 mile) and was never designed for distance.
How to spot it, plus an explanation of why meteors in annual showers have radiant points.
The image above is one of the highest resolution images ever returned of Mercury. MESSENGER acquired it on June 11, 2014. Last Friday – July 25, 2014 – MESSENGER’s periherm (closest point to Mercury) dropped below 100 kilometers / 62 miles. MESSSENGER is the first manmade object ever to come this close to Mercury.
As day ebbs into night on July 29, will you spot the young lunar crescent and the star Regulus as they make their fleeting appearance over the western horizon at dusk? From mid-northern North American latitudes, you might catch the elusive couple about 45 to 60 minutes after sunset – if you’re blessed with an unobstructed western horizon and crystal-clear skies. Binoculars may be helpful.
One of the most anticipated astronomical events of 2014 is the close passage of Comet C/2013 A1 Siding Spring to the planet Mars on October 19, 2014. The comet’s tiny nucleus, or core, will miss Mars by about 82,000 miles (132,000 kilometers). As comets travel through space, though, they leave behind a trail of dust particles, and this trail of debris might be wide enough to reach Mars and encounter its thin atmosphere … or might miss it, too. Follow the links inside to learn more.