The photo above showing a high-arching pink rainbow was captured at sunset near Durban, South Africa.
The camera is facing toward the anti-solar point. Like the setting Sun, the rainbow colors we’re familiar with acquire red or pink hues once the Sun dips close to the horizon. This is because as the Sun sets (or rises) the increased path length sunlight takes through the atmosphere acts to scatter out the green, blue and violet colors from our view. — PhotoJacques JoubertSummaryJim Foster
On February 15 a chunk of rock about 50 meters wide will whiz by Earth at nearly 8 km/s, coming within 27,680 km of our planet’s surface — closer than many weather and communications satellites.
For those of you more comfortable with imperial units, that’s 165 feet wide traveling 17,800 mph coming within 17,200 miles. But regardless whether you prefer meters or miles, in astronomy that’s what’s called a close call.
Scientists stress that there’s no danger of an impact by this incoming asteroid, designated 2012-DA14, but it’s yet another reminder that in our neck of the Solar System we are definitely not alone.
“2012-DA14 will definitely not hit Earth,” says JPL’s near-Earth object specialist Don Yeomans. “The orbit of the asteroid is known well enough to rule out an impact.”
But with 2012-DA14′s upcoming February flyby Yeomans notes, “this is a record-setting close approach.”
The rocky asteroid will come within about 4 Earth radii, which is well within the orbits of geosynchronous satellites. During its closest approach at 19:26 UTC it should be visible in the sky to amateur telescopes (but not the naked eye), becoming as bright as an 7th- or 8th-magnitude star.
Radar observatories will be watching 2012-DA14 during the days leading up to and following its approach in an attempt to better determine its size, shape and trajectory. NASA’s Goldstone facility will have an eye — er, dish — on DA14, but it won’t be visible to Arecibo. Stay tuned for more info!
Read more about 2012-DA14 on the JPL Near-Earth Object Program page here.
How do coral reef conservationists balance the environmental needs of the reefs with locals who need the reefs to survive? Joshua Drew draws on the islands of Fiji and their exemplary system of protection, called “connectivity”, which also keep the needs of fishermen in mind.
Lesson by Joshua Drew, animation by Veronica Wallenberg
The Mississippi River delta, as imaged by Japan’s Advanced Land Observing Satellite. As 17,000 cubic meters of water pump out every second, vegetation (here colored red) is fed by the rich sediment. The fractal nature of its branching is a natural property that emerges from finding the most efficient branch pattern to feed a large surface area.
MinutePhysics brings us the top 10 reasons why we know the Earth is round.
It’s something that’s completely obvious now that we’ve, you know, been out in space and seen it for ourselves and all. But there’s some interesting observations that tell us that we live on a sphere*.
I think my favorite bit is the triangle with three 90˚ turns. Perhaps the most famous experiment to determine a round Earth was done in ancient Egypt by Eratosthenes, famously measuring the difference in high-noon shadows shadows of two distant towers. Let Carl Sagan tell you all about it.
Ever since our planet formed from a cloud of condensed stellar dust, the dense heat of our interior has created a molten core surrounded by a thin candy shell of solid rock. That shell continues to evolve, leaking magma via cracks in its moving surface, via events both quiet and violent.
Such is the continual evolution of our planet. It’s a beautiful process, assuming you’re looking at it in a photograph, rather than while running in fear from the bottom of the mountain where it’s occurring.
The data was acquired over nine days in April 2012 and 13 days in October 2012. It took 312 orbits to get a clear shot of every parcel of Earth’s land surface and islands. This new data was then mapped over existing Blue Marble imagery of Earth to provide a realistic view of the planet.
The image was made possible by the satellite’s “day-night band” of the Visible Infrared Imaging Radiometer Suite, which detects light in a range of wavelengths from green to near-infrared and uses filtering techniques to observe dim signals such as city lights, gas flares, auroras, wildfires and reflected moonlight.
The day-night band observed Hurricane Sandy, illuminated by moonlight, making landfall over New Jersey on the evening of Oct. 29. Night images showed the widespread power outages that left millions in darkness in the wake of the storm.
A massive crack in the ice may herald an enormous rift in the ice of the Pine Island Glacier in western Antarctica.
Credit:NASA Goddard Space Flight Center
Satellite images suggest that the glacier is poised to calve off an iceberg or icebergs that size of New York City. Sea ice has kept the unstable region locked in, but as this Oct. 26, 2012 Landsat 7 image reveals, the spring melt has cleared the sea in front of the glacier’s calving face.