One of the fascinating aspects of viewing Earth at night is how well the lights show the distribution of people. In this view of Egypt, we see a population almost completely concentrated along the Nile Valley, just a small percentage of the country’s land area.
The Nile River and its delta look like a brilliant, long-stemmed flower in this astronaut photograph of the southeastern Mediterranean Sea, as seen from the International Space Station. The Cairo metropolitan area forms a particularly bright base of the flower. The smaller cities and towns within the Nile Delta tend to be hard to see amidst the dense agricultural vegetation during the day. However, these settled areas and the connecting roads between them become clearly visible at night. Likewise, urbanized regions and infrastructure along the Nile River becomes apparent (see also The Great Bend of Nile, Day & Night.)
Another brightly lit region is visible along the eastern coastline of the Mediterranean—the Tel-Aviv metropolitan area in Israel (image right). To the east of Tel-Aviv lies Amman, Jordan. The two major water bodies that define the western and eastern coastlines of the Sinai Peninsula—the Gulf of Suez and the Gulf of Aqaba—are outlined by lights along their coastlines (image lower right). The city lights of Paphos, Limassol, Larnaca, and Nicosia are visible on the island of Cyprus (image top).
Scattered blue-grey clouds cover the Mediterranean Sea and the Sinai, while much of northeastern Africa is cloud-free. A thin yellow-brown band tracing the Earth’s curvature at image top is airglow, a faint band of light emission that results from the interaction of atmospheric atoms and molecules with solar radiation at approximately 100 kilometers (60 miles) altitude.
Photograph by Stéphane Guisard, European Southern Observatory
Viewed through an amateur telescope, the Milky Way’s dusty center sweeps diagonally across the sky, draping stellar nurseries. Behind the veil lurks the supermassive black hole at the center of our galaxy.
Astronomers for the first time have peered into the heart of a supernova that exploded 343 years ago. NASA’s NuSTAR mission has produced the first map of high-energy X-ray emissions from material created in the core of the exploding star.
Read more: http://bit.ly/MKip1s via UC Berkeley
through Science Alert
NASA’s Curiosity Mars rover reached the edge of a dune on Jan. 30 and photographed the valley on the other side, to aid assessment of whether to cross the dune.
Curiosity is on a southwestward traverse of many months from an area where it found evidence of ancient conditions favorable for microbial life to its long-term science destination on the lower slopes of Mount Sharp. Based on analysis of images taken from orbit by NASA’s Mars Reconnaissance Orbiter, a location dubbed “Dingo Gap” was assessed as a possible gateway to a favorable route for the next portion of the traverse.
A dune across Dingo Gap is about 3 feet (1 meter) high, tapered off at both sides of the gap between two low scarps. Curiosity reached the eastern side of the dune on Jan. 30 and returned images that the rover team is using to guide decisions about upcoming drives.
Image credit: NASA
Crescent Moon Rising and Earth’s Atmosphere - On Feb. 1, 2014, Japan Aerospace Exploration Agency astronaut Koichi Wakata tweeted this view of a crescent moon rising and the cusp of Earth’s atmosphere. Distinct colors are visible because the dominant gases and particles in each layer of the atmosphere act as prisms, filtering out certain colors of light.
Image Credit: NASA
If there was ever life on Mars, it’s likely this would have been the mud it lived in, according to the analysis of minerals on the rim of the Endeavour Crater by Opportunity. NASA’s newest rover Curiosity has already found traces of fresh water on the Red Planet, but in a dried-up lake 8,000 km away and hundreds of millions of years later. Together, the findings suggest not only that habitable environments existed on Mars, but that they existed under different environmental conditions.
Read more: http://bit.ly/M8dZkw
Andromeda is headed our way at about seventy five miles per second.
In about three or four hundred billion years the Andromeda and Milky Way galaxies will collide. The result, if anybody is around to see it, will be beautiful. The two galaxies will pass through each other first. There is so much empty space, and the distance between stars so great, that it’s extremely unlikely that any stars will actually collide. But dust and gas clouds will, and that means that the rate of star creation will be greatly boosted.
Additionally, supernovae (which currently happen within either galaxy every 50 years or so) will likely start happening about once a year with some of them being close enough to outshine all the rest of the stars as seen from Earth.
Having passed through on a grazing course, Andromeda will retreat for a while, and then come back for a head-on collision. This time, the super-massive black holes at the centers of the galaxies will pass close enough together to pull each other in and merge. Gravitational waves will fling many stars out of the galaxies into intergalactic space, and will pull many others closer to the core. There’s a good chance that our sun (which will be a bit bigger, but still exist) along with its planets (Earth will still be there, but it will be parched and lifeless) will get pulled towards the center of the combined galaxies and then flung outward. (There’s a smaller chance that the flinging could send us right into one of the black holes.)
Our night sky right now is beautiful. But compared to what will be visible during these goings-on, it’s downright dull. The sky will be filled with so many stars that the night will no longer be dark. Gas clouds will glow brightly and in many colors. If we get close enough to the center, we’ll even be able to see massive gas jets shooting from the black holes in the core.
Shortly thereafter, the sun will finally expand to engulf the Earth bringing our planet to its final demise. But what an exit!!
(That article is about eight years old, but still accurate. The most substantive change to our knowledge since then is the confirmation in 2012 via Hubble data that the collision is, in fact, inevitable.)
Photograph by NASA, ESA and the Hubble Heritage Team (STScI/AURA)
A holiday greeting from Hubble! The storied space telescope celebrates the season with this image of a starry explosion that resembles a holiday ribbon.
The knots in planetary nebula NGC 5189 each measure roughly the size of our solar system.
The ribbon shape of the nebula is sculpted by its central star, which wobbles as it rotates. “Reminiscent of a lawn sprinkler,” the Hubble team says of the nebula image, the most-detailed look ever of this intriguing object.
from Nat Geo
Photograph by NASA/JPL/University of Arizona
Tithonium Chasma is just one branch of Valles Marineris, which stretches some 2,500 miles (4,000 kilometers) across the face of Mars. Seen from overheard in a Mars Reconnaissance Orbiter image, light and dark strips of sediment are shown lining the chasm.
Astronomers suspect the fine lines etched across those sandy layers may date to a change in the tilt of the red planet hundreds of millions of years ago. An ancient shift from a 50° planetary tilt to today’s more modest 25° one, may have melted ice and released the water that etched the channels.
from Nat Geo