From odd flowers to the birth of stars and Antarctica to Saturn, here are the best images we've found this week.
1. Rocks in 3D
A geologist and an architect standing in a lab may sound like the start to a very nerdy joke, but a pair of these professionals have joined together to revolutionize the way scientists study structures, such as fossils, inside rocks.
Geologists use a variety of techniques to analyze fossils and other features trapped inside Earth's rocky layers. The most basic technique, dating back to the 19th century, involves slicing away layers of rock, taking pictures of each layer, and then recreating the full 3D shapes by connecting dots between images. But this method is tedious and prone to human error.
2. Contaminated frogs
Pesticides from California's valley farms are collecting in the tissues of a singing treefrog that lives in pristine national parks, including Yosemite and Giant Sequoia, a new study finds.
The chemicals include two fungicides never before found in wild frogs, said Kelly Smalling, lead study author and a U.S. Geological Survey (USGS) research hydrologist. The study was published today (July 26) in the journal Environmental Toxicology and Chemistry.
3. Unimpressed peahens
A male hoping to attract a female's attention typically needs something to help him stand out from the crowd, and the inhabitants of the animal kingdom are no exception, with peacocks representing particularly showy lovers.
However, in a new study, researchers found that even though peacocks put on some of the most striking and theatrical courtship displays, peahens almost always gazed at the lower part of the peacock's train of feathers, particularly below the neck.
4. Violent short-lived stars
New observations by a powerful telescope in Chile have revealed clues into why some galaxies experience a frenetic period of rapid star birth, only to see those stellar new-borns starve future generations of stars.
Scientists studying the artfully named Sculptor Galaxy found that as its stars are born and die, they blow away the rich gas material needed to create more stars, blasting it out of the galaxy, possibly forever.
5. Melting permafrost
Antarctica's Dry Valleys are home to the oldest ice on Earth. The first signs of the massive thaw disturbing the Arctic's frozen ground have now appeared in one of these valleys, melting a glacier buried since the last Ice Age.
The Dry Valleys are different from the rest of Antarctica. Their ice, some of which is millions of years old, is buried under scoured boulders and dust as fine as flour. The arid landscape looks like Mars and, until now, hadn't changed much since the continent froze about 15 million years ago.
6. Hubble's amazing views
With the Hubble Space Telescope's successor, the James Webb Space Telescope, on schedule to reach outer space in 2018, taking Hubble's place as NASA's premier eye in the sky, it seems appropriate to look back on what may become Hubble's most enduring legacy: its stunning images. Besides the huge amount of data Hubble has collected since its launch in 1990, the telescope will likely be remembered most for its gorgeous colour shots of nebulas, galaxies and the early universe, iconic images that seemed tailor made for magazine covers and bedroom walls.
But throughout the storied history of the Hubble Space Telescope, the beauty of those colour images has sometimes overshadowed one important question: Where does that colour come from? After all, some of Hubble's amazing photos - and images from other space telescopes, for that matter - depict astronomical objects in ultraviolet or infrared light. But the human eye can't perceive those colours. When people look at a Hubble image showing these hues, what exactly are they seeing?
7. Smelly but beautiful
A corpse flower in its death throes doesn't smell like a corpse at all.
A titan arum (or "corpse flower") housed here at the U.S. Botanic Garden Conservatory has been smelling up its exhibition hall to the delight of thousands of visitors since the tropical flower finally went into full bloom on Sunday (July 21), but its time in bloom is quickly coming to a close.
8. Weird hero shrew
The hero shrew - a small, rat-like animal with a bizarrely strong and oddly shaped backbone - has mystified scientists since it was first described more than 100 years ago. Now, a newly discovered species of hero shrew may help researchers piece together why the animal evolved to have such a peculiar spine and what purpose the hardy backbone serves now.
The hero shrew's unique backbone gives the animal extraordinary strength, said lead study author William Stanley, collections manager of mammals at The Field Museum in Chicago. The animal's lower back has 10 to 11 lumbar vertebrae (the bones that make up the lower spine) that jut out and interlock with one another, he added. In comparison, humans have five lumbar vertebrae between the rib cage and the pelvis that help support the weight of the body.
9. Poor seals!
Harp seals mate and rear their young on the sea ice off the east coast of Canada in the spring and move north as the weather warms. But increasing numbers of seals are ending up stranded along the U.S. East Coast, as far south as the Carolinas, far away from where they should be at this time of year.
As ice levels in the North Atlantic have declined, the number of seals that have wound up on beaches, either dead or in poor health, has increased, new research shows.
10. Earth from Saturn
It's not often that some event comes along to really show humanity its true place in the universe, but two NASA spacecraft have just managed just that.
I'm talking, of course, about the spectacular NASA photos of Earth as it appeared from Saturn - nearly 900 million miles away (1.4 billion kilometres) - as well as a photo of our planet as it appeared from Mercury, nearly 61 million miles (98 million km) distant. NASA took the photos Friday (July 19) using the Cassini spacecraft around Saturn and the Messenger spacecraft around Mercury as part of a global campaign to show the world how the solar system views our planet Earth. The space agency even worked to coordinate campaigns to involve space fans by having them wave at Saturn. The images, by far, are amazing. Earth and its moon stand out as bright pinpricks of light in Messenger's view from Mercury, while our planet is a pale, fuzzy dot nestled between Saturn's rings in the Cassini view.
11. Madagascar sights
Credit: Satanic Leaf-tailed gecko image via Shutterstock
Madagascar, a large island in the Indian Ocean, may have only 1 percent of the world's land area, but it has an outsize 3 percent of its species. It is among the most diverse places for life on Earth.
But the process that put Madagascar on this list - the evolution of new species - may have slowed down, a new study suggests.
12. Flavour-shifting particles
Exotic particles called neutrinos have been caught in the act of shape-shifting, switching from one flavour to another, in a discovery that could help solve the mystery of antimatter.
Neutrinos come in three flavours - electron, muon and tau - and have been known to change, or oscillate, between certain flavours. Now, for the first time, scientists can definitively say they've discovered muon neutrinos changing into electron neutrinos.
13. Stark Antarctica
One of the wild cards in estimating future sea level rise from global warming is the enormous East Antarctic Ice Sheet, which holds more freshwater in its icy expanse than the whole of Greenland.
Some climate models predict the giant ice sheet will undergo relatively little change as the planet warms in coming decades, while others forecast significant melting. Now, a new study suggests parts of the East Antarctic Ice Sheet underwent significant melting during the Pliocene, a recent geologic epoch when climate conditions were similar to those of today.
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