Ben Cooper / LaunchPhotography.com

An oxygen tank from the Skylab Space Station, the largest of several pieces that were recovered from America's first space station following its re-entry in 1979, wrapped in protective plastic.

By Ben Cooper
Space.com

NASA celebrates the 40th anniversary on Tiuesday of the launch of Skylab, America's first space station, but you might be surprised where this icon of U.S. human spaceflight ended up.

After hosting rotating astronaut crews from 1973-1974, the Skylab space station eventually fell back to Earth in pieces that landed in Australia. Now, decades later, many of those pieces are on display at Australian museums, offering a fascinating glimpse into America's first stab at living in space.

From May 1973 to February 1974, Skylab saw a trio of three-man crews take up residence aboard the outpost, before it was abandoned with the plan of possibly using the space shuttle (then under development) to reactivate the laboratory. But with no way to reboost Skylab to a higher orbit to keep it aloft, and delays in getting the shuttle off the ground, the space station re-entered the Earth’s atmosphere over the southern Indian Ocean in 1979, with pieces landing inland along the south coast of Western Australia. [See more photos of Skylab's remains in Australia]

The mostly uncontrolled re-entry was a media sensation at the time, with newspapers offering prizes for the first debris found and to persons impacted by falling pieces. NASA's attempt at sending Skylab into the Indian Ocean, out of harm's way, proved only somewhat successful, and the spacecraft entered several minutes earlier than predicted, slightly off course.

NASA

Skylab astronauts took this photograph as they approached the orbiting laboratory on the third and final mission in November 1973

Several large chunks and dozens of smaller pieces of Skylab survived the fiery plunge through the atmosphere and impacted the ground in the Australian outback over a large swath centered around the community of Balladonia on the Nullarbor Plain. The largest pieces included the oxygen tanks designed to keep the crew alive during their stays.

Skylab on display
Visitors can almost miss Skylab. Tucked away in a large display case in a small city museum, the remains of what fell from the sky on July 11, 1979, can be found in Esperance, a port town with less than 10,000 inhabitants located 450 miles from Perth, which is the only major city in the western half of the sparsely populated country. Esperance was directly under the path of Skylab's re-entry. [How NASA's Skylab Space Station Worked (Infographic)]

On the outside, the corrugated metal walls and roof of the museum have the appearance of four long warehouses. That's because the Esperance Municipal Museum, founded in 1976 on the site of a former railroad yard, is composed of converted train equipment sheds.

From the main road along the waterfront in Esperance, a small blue and yellow sign hung on the side of the building is all that denotes it as a "museum," and a larger hanging billboard makes note of the main attraction inside: "In 1979, a spaceship crashed over Esperance. We fined them $400 for littering." A stamp next to it reads, "PAID IN FULL."

Ben Cooper / LaunchPhotography.com

The small Esperance Municipal Museum is located near the waterfront of the port town of about 10,000. A large model of Skylab stands on a pedestal at the museum's entrance.

It's true. The local government slapped NASA with a comical $400 bill for the cleanup, though the U.S. space agency never officially paid up. However, on the 30th anniversary of the crash in 2009, a radio host for Highway Radio in California and Nevada used his program to raise the funds and put a formal end to the complaint. The paycheck now hangs above the remains.

Spacecraft remains
Around the front of the museum, a large model of the space station sits at a sharp angle atop a pedestal. A plaque on the side describes the space station and what happened along this lonely coastline a few decades ago.

Inside, most of what remains of Skylab can be found in a large Plexiglas-enclosed display case. The largest oxygen tank sits on the floor adjacent to it, wrapped in plastic. Inside the case, the largest intact pieces are displayed at center. These include the space station's storage freezer for food and other items, a water tank, nitrogen spheres for the station’s attitude control system thrusters and a piece of what is identified as a portion of the hatch the astronauts would have crawled through during their visits. Many smaller pieces of debris are laid out around the larger chunks, each labeled and identified where possible.

Ben Cooper / LaunchPhotography.com

The oversized check by the Nevada & California-based radio station The Highway, used to finally pay a $400 litter fine after 30 years, is on display.

Several news articles and photographs circle the case, including photos showing the actual re-entry taken by locals and one featured in a National Geographic story from October 1979. The oversized check created by the Nevada radio station, which was used to pay the litter fine, sits proudly above it, and a proclamation from Barstow proclaiming July 13, 2009, as "Shire of Esperance/Skylab Day" lies mounted on a plaque alongside a key to the city.

Portions of the debris were sent elsewhere to be displayed, such as in the United States and Sydney. And it is possible that other pieces of debris remain in the remote outback, still waiting to be found.

If you visit Skylab
If you are visiting Western Australia, the Esperance Municipal Museum is located on James Street, between the waterfront Esplanade and Dempster Street. There is a $4 admission fee. Allow 30 minutes if your goal is to see Skylab only.

Another of the large oxygen tanks that survived Skylab's fall to Earth is on display at the U.S. Space & Rocket Center in Huntsville, Ala. The Powerhouse Museum in Sydney also has a portion of a titanium sphere in its collection, but it is not believed to be on display right now.

Follow us on Twitter @Spacedotcom, Facebook and Google+. Original article on Space.com.

• Skylab: The First U.S. Space Station (Photos)
• Space Station Evolution: 6 Amazing Orbital Outposts
• Cosmic Quiz: Do You Know the International Space Station?

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Starry Night software

The annular eclipse of the sun by the moon, as it will appear from Cooktown, Queensland, Australia on Friday morning at 8:49 a.m. local time.

By Joe Rao
Space.com

A spectacular "ring of fire" solar eclipse will be visible from northern Australia Friday morning local time, treating lucky skywatchers in the region to their second solar eclipse in less than six months.

During this week's annular solar eclipse, which begins late Thursday Eastern time due to time zone differences,  the moon's disk will appear to be about 4.5 percent smaller than the disk of the sun, so the effect is like placing a penny atop a nickel. A ring of sunlight remains visible surrounding the moon, resulting in a ring of fire, or annular, solar eclipse. 

The shadow path from which the ring will be visible runs for thousands of miles, but will get no wider than 107 miles (172 kilometers) at the point of greatest eclipse. Much of the path falls over the Pacific Ocean, but at or soon after local sunrise Friday (when it will actually be Thursday in North America), it will slice across a part of northern Australia. [See Spectacular Photos of a 'Ring of Fire' Solar Eclipse]

And in Queensland, amazingly, the eclipse track passes over the very same area that experienced a total solar eclipse last November! Places that fortuitously find themselves within the pathof both eclipses include Kowanyama, Maramie, and Dixie. The center lines of the two eclipses end up crossing just to the northeast of Mitchell-Alice Rivers National Park. 

A rare event
Just how often does the same region get two solar eclipses in less than six months? Certainly it would seem to be an exceptionally rare occurrence.  

The mean frequency of a total solar eclipse for any given spot on Earth is once every 375 years, and it's once every 224 years for annular eclipses, according to the famous Belgian eclipse calculator Jean Meeus, By combination, this yields an annular or a total eclipse every 140 years. 

Eclipse predictions by Fred Espenak, NASA / GSFC

The first solar eclipse of 2013 occurs at the moon's descending node in eastern Ares. An annular eclipse will be visible from Australia, eastern Papua New Guinea, the Solomon Islands and the Gilbert Islands.

But the paths of total and annular solar eclipses, while narrow, can also run for thousands of miles across the surface of the Earth. And sometimes, the paths of two different eclipses cross each other after a short time interval, as happens with the eclipses of November 2012 and May 2013. 

When the moon passes squarely in front of the sun and either completely obscures it or allows a ring of sunlight to remain, we call that a "central" eclipse. A little less than six months is the shortest time interval you can have between two central eclipses. 

WARNING: Never look directly at the sun during an eclipse with a telescope or your unaided eye; severe eye damage can result. Scientists and serious eclipse-watchers use special filters to safely view these events. [How to Safely Observe the Sun (Infographic)]

Coming attractions
Interestingly, during the 20th century such back-to-back solar eclipses occurred 12 times. But during the 21st century, it happens 23 times.

Prior to 2012-2013, the last time this happened was in 2009-2010 over China. A very long (almost seven-minute) total eclipse occurred on July 22, 2009, followed on Jan. 15 by an annular solar eclipse.

Chongqing, the largest and most populous of China's four provincial-level municipalities (population 31.4 million) was in the totality path in July 2009. Six months later, it ended up on the central line of annularity, with the ring phase lasting 7 minutes and 50 seconds.

The next time this will happen after this week involves two annular eclipses, on Dec. 26, 2019 and June 21, 2020. In fact, the two eclipse tracks will cross each other not once but twice — first over Arabia and later over the Pacific Ocean. 

And if you live in south-central Texas, the track of an annular eclipse on Oct. 14, 2023 will cross with the track of a total eclipse on April 8, 2024. The middle of each track (roughly 120 miles, or 200 km, wide) will intersect 10 miles (16 km) north of Utopia, Texas which is located to the west of San Antonio. 

The annular eclipse will last five minutes, while the total eclipse will run an unusually long 4 minutes 26 seconds. Amazing!

Eclipse drought will soon end
While we’re on the subject of successive central solar eclipses in certain places, it's worth pointing out that there are other parts of the globe suffering a solar eclipse drought. 

Take, for example, northern New York state and much of central and northern New England. The last time an eclipse of the sun was visible from these places was on Christmas Day, 2000.

But the wait will finally come to an end later this year when, on Nov. 3, the latter stages of a partial solar eclipse will be visible at sunrise for the Eastern Seaboard, including upstate New York and New England.

Editor's note: If you live in the observing area of this week's solar eclipse and safely snap an amazing picture of the sun that you'd like to share for a possible story or image gallery, send photos, comments and your name and location to Managing Editor Tariq Malik at spacephotos@space.com.     

Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for Natural History magazine, the Farmer's Almanac and other publications, and he is also an on-camera meteorologist for News 12 Westchester, N.Y. Follow us @Spacedotcom, Facebook and Google+. Original article on Space.com.

• How to Safely Photograph the Sun (A Photo Guide)
• Solar Eclipse & Evening Planets - May 2013 Skywatching Guide | Video
• Solar Eclipses: An Observer's Guide (Infographic)

Copyright 2013 Space.com, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

Support Our Sharks.

A male mandarin dogfish shark that was caught along with a pregnant female in the waters off western Australia, far from their usual stomping grounds near Indonesia.

By Tia Ghose
LiveScience

A rare shark couple found for the first time off the coast of Australia may force a rethink of the species' range.

Two years ago, a sport fisherman caught a pair of rare sharks off Rottnest Island in Western Australia. The duo, a male shark about 3.3 feet (1 meter) long and a pregnant female about 3.9 feet (1.2 m) long, looked different from the sharks that normally prowl the Australian waters. The female was carrying 22 pups.

The fishermen gave the sharks to ocean researchers at the University of Western Australia. After analyzing the sharks' DNA, the team concluded that the sharks were mandarin dogfish sharks, which are normally seen only in the waters off Indonesia, Japan and New Zealand.

"After two years of thorough investigation which included DNA sequencing, the sharks were identified as mandarin dogfish (Cirrhigaleus barbifer), a species never before seen in Australia," said study co-author Ryan Kempster, a marine neuroecologist at the conservation group Support Our Sharks.

Support Our Sharks

An X-ray image of a mandarin dogfish shark found in Australian waters, far from what was thought to be its only habitat around Indonesia.

The new discovery reveals that the shark has a much larger range than previously thought. The scientists don't know exactly why the sharks strayed so far from their normal habitat.

The discovery of 22 pups was also a surprise. Scientists have only discovered two other pregnant sharks of this species, and those specimens weren't carrying so many sharks.

"Previously, it was thought that the maximum number of pups for this species was 10," Kempster said in a statement.

The analysis of the sharks was published Thursday in the journal Marine Biodiversity Records.

Follow Tia Ghose on Twitter @tiaghose or OurAmazingPlanet @OAPlanet. We're also on Facebook and Google+.

• On the Brink: A Gallery of Wild Sharks
• Images: 17 Amazing Sea Creatures You've Never Heard Of
• In Images: The Fantastic Fishes of Shark Island

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Courtesy of The Tasmanian National Museum and Gallery

Tasmanian tigers (Thylacinus cynocephalus) looked somewhat like striped coyotes and were found throughout most of the Australian island of Tasmania before Europeans settled there in 1803.

By Megan Gannon
LiveScience

Humans alone were responsible for the Tasmanian tiger's extinction in the 20th century, according to a new study that shoots down claims that disease also doomed the meat-eating marsupial.

More officially known as thylacines, Tasmanian tigers (Thylacinus cynocephalus) looked somewhat like striped coyotes and were found throughout most of the Australian island of Tasmania before Europeans settled there in 1803.

Starting at the end of the 19th century, the Tasmanian government paid bounties for thylacine carcasses, as the animals were believed to prey on farmers' sheep and poultry. (A recent study, however, showed that the carnivores' jaws were so weak they likely couldn't have taken down anything larger than a possum.) Humans eventually hunted thylacines to extinction in the early 1900s; the last known individual died in a Tasmanian zoo in 1936.

"Many people, however, believe that bounty hunting alone could not have driven the thylacine extinct and therefore claim that an unknown disease epidemic must have been responsible," researcher Thomas Prowse of Australia's University of Adelaide said in a statement.

Prowse and his colleagues developed a mathematical model to evaluate whether the combined impacts of Europeans' settlement could have wiped out the thylacine, without any disease involved.

"The new model simulated the direct effects of bounty hunting and habitat loss and, importantly, also considered the indirect effects of a reduction in the thylacine's prey (kangaroos and wallabies) due to human harvesting and competition from millions of introduced sheep," Prowse said.

Indeed, their results, published this month in the Journal of Animal Ecology, showed that these impacts alone would have been powerful enough to send the Tasmanian tiger population crashing in the early 20th century.

A study out last year suggested that low genetic diversity eventually would have set the thylacine on a path to extinction even if they hadn't been hunted off the planet.

The tiger's extant cousin, the Tasmanian devil, is currently being wiped out by a contagious cancer that's been able to spread all the easier because of the devil's low genetic diversity, which cuts down a wildlife population's ability to adapt to changing environmental conditions and bounce back from disease and mass fatalities. The Tasmanian tiger, if around today, also would be exceptionally susceptible to diseases, those researchers said.

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• Wipe Out: History's Most Mysterious Extinctions
• Australia's Struggling Marsupial: Photos of the Tasmanian Devil
• The 10 Weirdest Animal Discoveries of 2012

Francis Tsang / Getty Images file

Researchers detected substantial gene flow from Indian populations into Australia about 4,230 years ago. At about the same time, the dingo first appears in the Australian fossil record, an animal that most closely resembles Indian dogs.

By Charles Choi, LiveScience contributor

Indians migrating to Australia more than 4,000 years ago may have introduced dingoes to the island continent, along with novel stone tools and new ways to remove toxins from edible plants, researchers say.

Australia was thought to have remained largely isolated from the rest of the world between its initial colonization about 40,000 years ago by the ancestors of aboriginal Australians and the arrival of Europeans in the late 1800s.

"Outside Africa, aboriginal Australians are the oldest continuous population in the world," said researcher Irina Pugach, a molecular anthropologist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.

Still, researchers had not really explored the genetic history of Australians in great enough detail to address this question.

Isolated continent?
"The extent of isolation of aboriginal Australia has been debated for a long time," Pugach told LiveScience. "The Australian archaeological record documents some changes that occur in Australia around 4,000 years ago, which could have been potentially, but not necessarily, brought in from the outside."

To find out more, the researchers analyzed DNA from 344 people, including aboriginal Australians, highlanders of Papua New Guinea, Southeast Asian islanders, Indians, Nigerians, individuals of European descent living in Utah and Han Chinese from Beijing.

The scientists found a common origin for populations from Australia, New Guinea and the Mamanwa, a group from the Philippines. The researchers estimate these groups split from one another about 36,000 years ago. This supports ideas that the groups descended from an ancient southwards migration out of Africa.

The researchers also detected substantial gene flow from Indian populations into Australia about 4,230 years ago. Scientists estimate this Indian genetic influence appears in about 10 percent of the aboriginal Australian populations they analyzed.

At about the same time, the dingo first appears in the Australian fossil record, an animal that most closely resembles Indian dogs.
In addition, at about that time, "archaeologists describe a sudden shift in stone tool technologies, with new implements known as the Small Tool Tradition appearing for the first time" in Australia, Pugach said. These represented stone tools that were smaller and more finely worked than before, she explained. [ Marsupial Gallery: Photos of Australia's Amazing Animals]

Moreover, at about that time, new techniques for altering dangerous plants to make them edible also appeared in Australia. For instance, while plants known as cycads can be toxic, soaking or fermenting their kernels can remove the poisons.

"Aboriginal Australians use the fruits of these plants as an important food source despite them being highly toxic," Pugach said.

The researchers caution the migration "may not have actually been from India, but from some population somewhere else that subsequently no longer exists, but whose closest living relative — at least, among populations we examined — are Dravidian-speakers from southern India," Pugach said.

The researchers also emphasized they are not claiming some Indian group members are the ancestors of aboriginal Australians. "The migration happened about 4,000 years ago. By that time, people [had] lived in Australia for more than 40,000 years," Pugach said.

It remains uncertain why this migration might have taken place more than 4,000 years ago. Environmental changes might be one cause, "although I don't know of any significant environmental changes then," Pugach said. Then again, it could "simply be wanderlust. Humans have always liked to migrate, and don't seem to need a reason to want to do so."

Future research can analyze additional Australian populations to see how widespread this Indian influence might actually be.

The scientists detailed their findings online Jan. 14 in the journal Proceedings of the National Academy of Sciences.

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• The 10 Weirdest Animal Discoveries of 2012
• 10 Surprising Ways Weather Has Changed History
• Top 10 Mysteries of the First Humans

© 2012 LiveScience.com. All rights reserved.

Australian Museum via Reuters

A Helen's Flying Frog perches on a branch in the Nui Ong Nature Reserve in Vietnam.

SYDNEY — An Australian biologist and her Vietnamese colleagues have made a surprise discovery — a new species of flying frog gliding and jumping around less than 60 miles from one of Southeast Asia's busiest cities.

Jodi Rowley and her team were conducting an amphibian survey between two patches of lowland forest in the middle of agricultural land criss-crossed by farmers and water buffalo each day, 56 miles (90 kilometers) from Ho Chi Minh City, when they made their find.

"And ... there on a log just sitting on the side of the path was this huge green flying frog," said Rowley, an Australian Museum biologist who specializes in amphibians. "To discover a previously unknown species of frog, I typically have to climb rugged mountains, scale waterfalls and push my way through dense and prickly rainforest vegetation."

The 4-inch-long (10-centimeter-long), bright green frog with a white belly managed to evade biologists until recently by gliding between treetops 20 yards (meters) up, only coming down to breed in temporary rain pools.

Though discovered in 2009, it has taken until now to identify it for certain as a new species. It has been named Helen's Tree Frog (Rhacophorus helenae) after Rowley's mother.

The discovery highlighted the need for conservation in lowland forests, which have come under huge threat, Rowley said. The two patches of trees that are home to Helen's Tree Frog are surrounded by rice paddies and agricultural land.

"We really don't know what's out there still in this part of the world," Rowley said.

She added that her mother, suffering from ovarian cancer, was very excited about having the "charismatic" amphibian named after her.

"I thought it was about time that I showed her how much I appreciate everything she's done for me," Rowley said.

Copyright 2012 Thomson Reuters. Click for restrictions.

By Tia Ghose
LiveScience

A 1,500-year drought in Australia may have led to the demise of an ancient aboriginal culture, a new study suggests.

The results, published Nov. 28 in the journal Geophysical Research Letters, show that geological traces of a mega-drought in the northwest Kimberley region of Western Australia coincide with a gap and transition in the region's rock art style. The finding suggests that the people who lived prior to the drought, called the Gwion, either left the region or dramatically altered their culture as a result of the drought, and a new culture called the Wanjinda eventually took its place.

"There is this significant gap in rock art. A possible reason for that is that the climate at that time changed so markedly that the artists who produced the Gwion art moved on from the Kimberley region," said study co-author Hamish McGowan, a climatologist at the University of Queensland in Australia.

But not everyone agrees with that interpretation. While the evidence for a drought is very convincing, archaeological sites show continuous occupation during that time, said Peter Veth, an archaeologist at the University of Western Australia who is an expert in the Kimberley's rock art and was not involved in the study.

"They reconfigure themselves on the land and often do portray things quite differently, but I don't see it as a different people," Veth told LiveScience.

Ancient inhabitants
Aboriginal cultures have inhabited Northwest Australia for the past roughly 45,000 years, McGowan said. But at least 17,000 years ago during the Pleistocene Era, a culture called the Gwion began depicting aspects of their life on the rocks in the region. The Gwion art depicted some extinct animals (such as a marsupial lion that went extinct during the last ice age) but also groups of slim figures in what look like ancient celebrations. [ Image Gallery: Europe's Oldest Rock Art ]

But between 5,000 and 7,000 years ago, traces of the Gwion rock art disappeared, and it wasn't until around 4,000 years ago when a new style of rock-art painting called the Wandjina, which depicts round faces with big eyes, emerged. It is still practiced today.

Pollen record
To understand why the rock art changed, McGowan and his colleagues analyzed sediments drilled from Black Springs, Australia. They found that around 6,300 years ago, the type of pollen started to change, suggesting a transition from a lush environment to one characterized by scrubby forests and open grasslands. The sediments also show an increase in dust, suggesting much drier conditions.

The results painted a picture of an ancient mega-drought that roughly coincided with the disappearance of Gwion art, McGowan said.

"The northwest of Australia can undergo very substantive natural changes in climate, which in the past have severely impacted aboriginal society," he told LiveScience, adding the climate change and disappearance of Gwion art suggest these people left the region.

But while it's likely that the drought radically altered the local societies, the rock art from the area isn't dated well enough to make conclusions about the complete disappearance of the culture, Veth said.

What's more, archaeological evidence suggests the area was continuously occupied, he told LiveScience. For instance, archaeologists find very similar stone tools throughout the drought, Veth said.

"They have identified a very interesting climate episode and it does seem to correlate with this switch — and that's the word I would use — a switch in the way people are portraying art," he said.

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• 10 Surprising Ways Weather Has Changed History
• Top 10 Mysteries of the First Humans
• Dry and Dying: Images of Drought

University of Queensland

This image shows a hybrid black tip shark containing both Common and Australian black tip DNA.

Hybrid sharks have been discovered swimming in the waters off Australia's east coast. The finding may be driven by climate change, a research team says, suggesting such discoveries could be more common in the future.

The hybridization is between the Australian black tip shark which favors tropical waters and the larger, common black tip shark, which favors sub-tropical and temperate waters.

While the distribution for the genetically distinct species overlaps along the northern and eastern Australian coastline, the finding that they mated and produced offspring is unprecedented, according to the discovery team from the University of Queensland.

"To actually find something like this and prove it genetically is unprecedented," Bob Hueter, director of the Center for Shark Research at the Mote Marine Laboratory in Sarasota, Florida, told me Tuesday.

Hueter was not involved with the research, though one of the scientists responsible for the discovery used to work in his lab, which he said lends the finding credibility. The finding is based on genetic testing and body measurements and reported December 2011 in the journal Conservation Genetics.

The team identified 57 of the hybrids from five locations spanning 1,250 miles along the Australian coast. 

"Wild hybrids are usually hard to find, so detecting hybrids and their offspring is extraordinary," Jennifer Ovenden, an expert in genetics of fisheries species and team member, said in a news release.

The hybridization could be an adaptation to climate change, the team noted, allowing the tropical Australian black tip shark to live in the cooler, sub-tropical waters. 

It could also be a technique to survive in over-fished waters, speculated Hueter. As fisheries are depleted, hybridization is a way to keep reproducing. 

"In a sense, it is catching evolution in action," he told me. 

More stories on hybridization:

• Wild find: Half grizzly, half polar bear
• Hybrid polar-grizzly bear a sign of Arctic's future
• Coyote + wolf = new breed of predator
• How warming is changing the wild kingdom