An ancient forest has thawed from under a melting glacier in Alaska and is now exposed to the world for the first time in more than 1,000 years.
Stumps and logs have been popping out from under southern Alaska’s Mendenhall Glacier — a 36.8-square-mile (95.3 square kilometers) river of ice flowing into a lake near Juneau — for nearly the past 50 years. However, just within the past year or so, researchers based at the University of Alaska Southeast in Juneau have noticed considerably more trees popping up, many in their original upright position and some still bearing roots and even a bit of bark, the Juneau Empire first reported last week.
"There are a lot of them, and being in a growth position is exciting because we can see the outermost part of the tree and count back to see how old the tree was," Cathy Connor, a geology professor at the University of Alaska Southeast who was involved in the investigation, told LiveScience’s OurAmazingPlanet. "Mostly, people find chunks of wood helter-skelter, but to see these intact upright is kind of cool."
The team has tentatively identified the trees as either spruce or hemlock, based on the diameter of the trunks and because these are the types of trees growing in the region today, Connor said, but the researchers still need to further assess the samples to verify the tree type.
A protective tomb of gravel likely encased the trees more than 1,000 years ago, when the glacier was advancing, Connor said, basing the date on radiocarbon ages of the newly revealed wood. As glaciers advance, Connor explained, they often emit summer meltwater streams that spew aprons of gravel beyond the glacier’s edge.
Saturn’s rings cut across an eerie scene that is ruled by Titan’s luminous crescent and globe-encircling haze, broken by the small moon Enceladus, whose icy jets are dimly visible at its south pole.
The scattered light around planet-sized Titan (5,150 kilometers, or 3,200 miles across) makes the moon’s solid surface visible in silhouette. Enceladus (505 kilometers, or 314 miles across) enjoys far clearer skies than its giant sibling moon.
This view shows the unlit side of Saturn’s rings.
High cliffs surrounding Echus Chasma on Mars
What created this great cliff on Mars? Did giant waterfalls once plummet through its grooves? With a four-kilometer drop, this high cliff surrounding Echus Chasma, near an impressive impact crater, was carved by either water or lava. A leading hypothesis is that Echus Chasma, at 100-kilometers long and 10-kilometers wide, was once one of the largest water sources on Mars. If true, water once held in Echus Chasma likely ran over the Martian surface to carve the impressive Kasei Valles, which extends over 3,000 kilometers to the north. Even if initially carved by water, lava appears to have later flowed in the valley, leaving an extraordinarily smooth floor. Echus Chasma lies north of tremendous Valles Marineris, the largest canyon in the Solar System. The above image was taken by the robotic Mars Express spacecraft currently orbiting Mars.
Image credit: G. Neukum (FU Berlin) et al., Mars Express, DLR, ESA
Science and Space Posters by Ron Guyatt
"Jim, I just lost my planet. I am emotionally compromised.”
This is a true color view of Saturn’s north polar region, taken by Cassini’s Imaging Science Subsystem (ISS) on June 26, 2013. You can see Saturn’s mysterious hexagon in the center.
Image Credit: NASA / JPL / SSI / composite by Val Klavans
These images were taken on June 26, 2013 and received on Earth June 27, 2013. The camera was pointing toward SATURN at approximately 402,383 miles (647,573 kilometers) away, and the images were taken using the CL1, RED, BL1 and GRN filters.
Marks on Martian dunes may be tracks of dry-ice sleds
NASA research indicates hunks of frozen carbon dioxide — dry ice — may glide down some Martian sand dunes on cushions of gas similar to miniature hovercraft, plowing furrows as they go.
Researchers deduced this process could explain one enigmatic class of gullies seen on Martian sand dunes by examining images from NASA’s Mars Reconnaissance Orbiter (MRO) and performing experiments on sand dunes in Utah and California.
The hillside grooves on Mars, called linear gullies, show relatively constant width — up to a few yards, or meters, across — with raised banks or levees along the sides. Unlike gullies caused by water flows on Earth and possibly on Mars, they do not have aprons of debris at the downhill end of the gully. Instead, many have pits at the downhill end.
The location of the linear gullies is on dunes that spend the Martian winter covered by carbon-dioxide frost. By comparing before-and-after images from different seasons, researchers determined that the grooves are formed during early spring
Scientists theorize the bright objects are pieces of dry ice that have broken away from points higher on the slope. According to the new hypothesis, the pits could result from the blocks of dry ice completely sublimating away into carbon-dioxide gas after they have stopped traveling.
Image credit: NASA/JPL-Caltech/Univ. of Arizona
I look up — many people feel small because they’re small and the Universe is big — but I feel big, because my atoms came from those stars. There’s a level of connectivity.
That’s really what you want in life, you want to feel connected, you want to feel relevant, you want to feel like a participant in the goings on of activities and events around you.
That’s precisely what we are, just by being alive…
- Dr. Neil DeGrasse Tyson [ x ]