According to folklore, this Friday's full moon is the Harvest Moon--a bright orb that shines down on the ripening fields of the northern hemisphere, allowing farmers to harvest their crops late into the night. The Harvest Moon of Sept. 16th won't be as bright as usual, though. It's going to pass through Earth's shadow, producing a penumbral lunar eclipse.

A penumbral eclipse happens when the Moon passes through the pale outskirts of Earth's shadow. It is much less dramatic than a total lunar eclipse. In fact, when observers are not alerted beforehand, they often do not realize an eclipse is underway. Nevertheless, the subtle shadow of Earth is visible to the naked eye if you know it's there.

Not every green light in the sky is the aurora borealis. On Sept. 2nd, Mike Taylor was in the Acadia National Park of Maine when he witnessed an intense display of airglow:
"It was the craziest airglow I've ever seen," says Taylor. "I was with 3 other photographers and we all saw this with our naked eyes."

Airglow is not an aurora. It's a chemical reaction involving oxygen in the upper atmosphere driven in part by solar ultraviolet radiation and cosmic rays. Visibility waxes and wanes with conditions such as pressure and temperature in the rarified air more than 90 km above Earth's surface. Gravity waves traveling up from the planet below impress the verdant glow with a dramatic rippling structure.

Dark nights with a new or thin crescent Moon are the best times to catch a glimpse of airglow. Often, the glow is dim and pale to the naked eye, revealing its green color only to the lens of cameras set for Milky Way-length exposures. On rare occasions, such as Sept 2nd in the Acadia National Park, the human eye is more than enough. Browse the airglow photo gallery for more sightings.

"It's amazing, shocking," said Glyn Collinson, a scientist at NASA's Goddard Space Flight Center on June 20th. "We never dreamt an electric wind could be so powerful that it can suck oxygen right out of an atmosphere into space. This is something that has to be on the checklist when we go looking for habitable planets around other stars."

Venus has an "electric wind" strong enough to remove the components of water from its upper atmosphere, which may have played a significant role in stripping Earth's twin planet of its oceans, according to new results from ESA's (European Space Agency) Venus Express mission by NASA-funded researchers.

Taking the electric wind into account will also help astronomers improve estimates of the size and location of habitable zones around other stars. These are areas where the temperature could allow liquid water to exist on the surface of alien worlds, making them places where life might be found. Some stars emit more ultraviolet light than the sun, so if this creates stronger electric winds in any planets orbiting them, the habitable zone around such stars may be farther away and narrower than thought.

Venus is in many ways the most like Earth in terms of its size and gravity, and there's evidence that it once had oceans worth of water in its distant past. However, with surface temperatures around 860 F (460 C), any oceans would have long since boiled away to steam and Venus is uninhabitable today.

Yet Venus' thick atmosphere, about 100 times the pressure of Earth's, has 10,000 to 100,000 times less water than Earth's atmosphere. Something had to remove all that steam, and the current thinking is that much of the early steam dissociated to hydrogen and oxygen: the light hydrogen escaped, while the oxygen oxidized rocks over billions of years.

Also the solar wind -- a million-mile-per-hour stream of electrically conducting gas blowing from the sun -- could have slowly but surely eroded the remainder of an ocean's worth of oxygen and water from Venus' upper atmosphere.

"We found that the electric wind, which people thought was just one small cog in a big machine, is in fact this big monster that's capable of sucking the water from Venus by itself," said Collinson.

Just as every planet has a gravity field, it is believed that every planet with an atmosphere is also surrounded by a weak electric field. While the force of gravity is trying to hold the atmosphere on the planet, the electric force (the same force that sticks laundry together in a drier and pushes electricity through wires) can help to push the upper layers of the atmosphere off into space. At Venus, the much faster hydrogen escapes easily, but this electric field is so strong that it can accelerate even the heavier electrically charged component of water -- oxygen ions -- to speeds fast enough to escape the planet's gravity. When water molecules rise into the upper atmosphere, sunlight breaks the water into hydrogen and oxygen ions, which are then carried away by the electric field.

Severe turbulence, which recently forced the emergency landing of a transatlantic flight, is on the rise. But why and what can be done?

United Airlines Flight 880 was carrying more than 200 passengers from Houston, Texas, to London's Heathrow airport two weeks ago when it was battered by turbulence that threw people on to the cabin ceiling. Twenty-three people were injured. "We were flying along as smooth as can be and then were just slapped massively from the top as if someone had torpedoed us," one passenger told journalists.

The aircraft, a Boeing 767-300, made an emergency landing at Shannon airport and the injured were taken to University Hospital, Limerick. No one was seriously hurt but all went through a terrifying experience and one, say experts, which will increasingly affect flights.

"It is predicted there will be more and more incidents of severe clear-air turbulence, which typically comes out of the blue with no warning, occurring in the near future as climate change takes its effect in the stratosphere," Dr Paul Williams, a Royal Society research fellow at Reading University, said last week.

"There has already been a steady rise in incidents of severe turbulence affecting flights over the past few decades. Globally, turbulence causes dozens of fatalities a year on small private planes and hundreds of injuries to passengers in big jets. And as carbon dioxide levels in the atmosphere keep on rising, so will the numbers of incidents."

Health officials are investigating after 47 birds fell from the sky in Boston's Dorchester neighborhood on Thursday.

Rescuers were able to save 15 of the birds, but 32 have died. Investigators are working to determine the cause, and whether the deaths of two cats in the neighborhood could be related.

"When I arrived, birds would fly, like from a house to a tree, they would flop in the tree and they would fall to the ground," said Alan Borgal of the Animal Rescue League of Boston. "The weaker ones were just falling right out the sky."

All the birds were grackles, black songbirds that typically travel in large flocks. They were found thrashing around on Bakersfield Street and the sidewalks nearby around 2 p.m.

"They couldn't get up," said resident Linda Veale.

"We don't know what is going on," said John Meaney of the city of Boston's Inspectional Services. "So we are investigating all avenues."

City officials are looking at everything from a virus, to environmental poisoning, to something intentional. They're also studying the many feeders neighborhood residents have outside.

A video appearing to show cloud-like shapes covering the ground in the region of Doukkala in Morocco was widely shared on social media after it was published on YouTube in February this year.


The video shows the whole area covered in a thick, foam-like substance.

Large chunks of the mysterious substance were captured on video rolling on the ground as if pushed by the breeze.

The people who filmed it said they were amazed by these mysterious substance.

The cameraman said that he has never seen a similar substance before and that he believes the substance is clouds that fell down from the sky.

"I have never seen clouds fall down to the ground. It is strange," he said.

The strangeness of the substance and rarity of such a phenomenon divided YouTube commenters on the logical explanation for the appearance of the thick foam.

A decade ago, Stephen Hawking warned that one of the major factors in the possible scarcity of intelligent life in our galaxy is the high probability of an asteroid or comet colliding with inhabited planets. This past December, a team of astronomers from Armagh Observatory and the University of Buckingham reported that the discovery of hundreds of giant comets in the outer planetary system over the last two decades means that these objects pose a much greater hazard to life than asteroids.

Giant comets, termed centaurs, move on unstable orbits crossing the paths of the massive outer planets Jupiter, Saturn, Uranus and Neptune. The planetary gravitational fields can occasionally deflect these objects in towards the Earth. Centaurs are typically 50 to 100 kilometer across, or larger, and a single such body contains more mass than the entire population of Earth-crossing asteroids found to date.

Because they are so distant from the Earth, Centaurs appear as pinpricks of light in even the largest telescopes. Saturn's 200-km moon Phoebe, depicted in this image, seems likely to be a Centaur that was captured by that planet's gravity at some time in the past. Until spacecraft are sent to visit other Centaurs, our best idea of what they look like comes from images like this one, obtained by the Cassini space probe orbiting Saturn. NASA's New Horizons spacecraft, having flown past Pluto six months ago, has been targeted to conduct an approach to a 45-km wide trans-Neptunian object at the end of 2018.

Calculations of the rate at which centaurs enter the inner solar system indicate that one will be deflected onto a path crossing the Earth's orbit about once every 40,000 to 100,000 years. Whilst in near-Earth space they are expected to disintegrate into dust and larger fragments, flooding the inner solar system with cometary debris and making impacts on our planet inevitable.

Known severe upsets of the terrestrial environment and interruptions in the progress of ancient civilisations, together with our growing knowledge of interplanetary matter in near-Earth space, indicate the arrival of a centaur around 30,000 years ago. This giant comet would have strewn the inner planetary system with debris ranging in size from dust all the way up to lumps several kilometres across.

Specific episodes of environmental upheaval around 10,800 BCE and 2,300 BCE, identified by geologists and palaeontologists, are also consistent with this new understanding of cometary populations. Some of the greatest mass extinctions in the distant past, for example the death of the dinosaurs 65 million years ago, may similarly be associated with this giant comet hypothesis.

An astronomer says a loud bang heard in Rolleston and a red streak seen in the sky over Whanganui at the same time were possibly from a meteorite entering Earth's atmosphere. Retired astronomer Peter Cottrell said it was possible the red streak and loud explosions late Saturday could be from a meteorite or space junk.

"It's possible to get a sonic boom from something coming through the atmosphere at high speed.

"It's a sonic boom because it is travelling faster than the speed of sound."

The red flash seen in Whanganui could have been the meteorite burning up in the atmosphere.

"As soon as it hits the atmosphere there's a lot of friction and friction creates heat and heat creates light as well."

Security guard Nick O'Leary, who was on duty at Whanganui Hospital, said he saw a red streak for a split second just after 11.30pm.

At the same time several residents in the town of Rolleston, Canterbury, reported loud explosions in the area.

Police were unable to identify the source.

Cottrell said the loud bang, or sonic boom, heard in Rolleston would have followed the sighting in Whanganui, Cottrell said.

If it had not burned up completely, finding the meteorite would be challenging. It could be as small as the size of a pebble, but would be dense and heavy.

Cottrell said it was fairly common for meteorites to enter Earth's atmosphere.

Portland, Oregon - Many people throughout the Pacific Northwest reported seeing a "fireball" blazing through the sky at around midnight Friday.

According to the American Meteor Society, more than 130 people reported seeing the light shoot across the sky. It was reported seen as far south as Grants Pass and as far north as Port Angeles, Washington. Most of the reports came from the Willamette Valley.

Videos and photos of the fireball were posted on social media.

For the first time, scientists have observed a deviation from the typical alternating pattern of easterly and westerly winds in the equatorial stratosphere.

The weather we experience on Earth typically occurs in the troposphere, the lowest layer of the atmosphere. But the stratosphere, which envelops the planet just above the troposphere, is home to winds of its own. In a new study, Newman et al. report an anomalous interruption in an otherwise reliable stratospheric wind pattern known as the quasi-biennial oscillation.

Each cycle of the quasi-biennial oscillation begins with strong westerly winds that flow through the stratosphere in a belt around the equator. Over the course of about 1 year, these winds gradually weaken and descend in altitude to the lower stratosphere as easterly winds replace them. These easterly winds slowly sink and weaken, too, as westerly winds return. The cycle repeats roughly once every 28 months.

Since 1953, scientists have observed equatorial winds by instruments known as radiosondes, which are carried skyward by weather balloons. The quasi-biennial oscillation was discovered in the early 1960s. Although the timing of each cycle has sometimes varied by a few months, the pattern as a whole has remained uninterrupted—until now.