Parts of the world are expected to light up with a green glow tonight, as a strong solar storm continues to blast our atmosphere.

The storm was caused by a hole in the outermost layer of the sun, opening the magnetic field up to stretch further than usual, which resulted in a gradual increase in the solar wind.

An increase in solar activity means the chances of seeing the Northern Lights, or Aurora Borealis, tonight in places like Canada, Scandanavia, Scotland and even northern England and are greater than usual.

Street and home lighting were turned off in the Icelandic capital, Reykjavik, for one hour to allow the world renowned Northern Lights spectacle to be viewed in all its glory.

The lights went out in selected parts of the city on Wednesday night and residents were asked to keep their homes in the dark between 10pm and 11pm to facilitate a clearer view of the spectacular natural phenomenon.

Needless to say, there are some risks to having a city-wide blackout and the Reykjavik City Council urged motorists in darkened areas to drive with particular caution.

Tourists and locals snapped awe-inspiring photos and videos of the dancing green-lit sky stretching across the capital.

The predicted combination of clear skies and high Aurora Borealis activity meant those who had traveled from all over the world to catch a glimpse of the celestial activity were in for envious views of the famously unpredictable event.

Scientists working with the Slooh observatories were able to take an image of Comet C/2016 R3, which was discovered by Russian astronomer Gennady Borisov on September 11, 2016. Since then, the comet has been too close to the sun to observe well, but Borisov and his peers think the celestial body might be one that was misplaced a century ago.

Comet C/2016 R3 was discovered by Gennady Borisov, an employee at Sternberg Astronomical Institute in Moscow, on September 11 this year. Earlier, Borisov spotted and catalogued four comets and one asteroid. He is working with observers using the Slooh global robotic observatory network.

Borisov together with Slooh member Bernd Luetkenhoener and Slooh astronomer Paul Cox have demonstrated that Comet C/2016 R3 is moving towards the sun and will reach its perihelion on October 12.

On September 20, a particular spot in the constellation Lupus the Wolf was blank of any stars brighter than 17.5 magnitude. Four nights later, as if by some magic trick, a star bright enough to be seen in binoculars popped into view. While we await official confirmation, the star's spectrum, its tattle-tale rainbow of light, indicates it's a nova, a sun in the throes of a thermonuclear explosion.

The nova, dubbed ASASSN-16kt for now, was discovered during the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the quadruple 14-cm "Cassius" telescope in CTIO, Chile. Krzysztof Stanek and team reported the new star in Astronomical Telegram #9538. By the evening of September 23 local time, the object had risen to magnitude +9.1, and it's currently +6.8. So let's see — that's about an 11-magnitude jump or a 24,000-fold increase in brightness! And it's still on the rise.

The star is located at R.A. 15h 29?, - 44° 49.7? in the southern constellation Lupus the Wolf. Even at this low declination, the star would clear the southern horizon from places like Chicago and further south, but in late September Lupus is low in the southwestern sky. To see the nova you'll need a clear horizon in that direction and observe from the far southern U.S. and points south. If you've planned a trip to the Caribbean or Hawaii in the coming weeks, your timing couldn't have been better!

Earth's ionosphere is a "conducting layer" that can transmit radio signals. To ensure the reliability of these transmissions, scientists must first understand how ionospheric variations influence radio signals and the drivers behind these variations.

One hypothesis holds that long-term trends in the ionosphere are related to the increase of carbon dioxide in lower layers of Earth's atmosphere. Perrone and Mikhailov take a different approach and consider the origin of long-term variations in the ionosphere as they relate to solar and geomagnetic activity—the so-called "geomagnetic control concept."

The authors scrutinized reliable observations of critical frequencies on European ionosondes for five solar cycles (around 55 years). Through their analysis, they've become the first to retrieve a consistent set of parameters—temperature and neutral composition—for the F layer, the region of the ionosphere transmitting the signals.

They found that their data reflect trends seen in long-term variations in solar and geomagnetic activity for the whole period, including the last deep solar minimum in 2008 - 2009.

The analysis confirms that the long-term variations have a natural origin: They existed in the past and presumably will continue in future, reflecting the long-term variations in solar activity.

Reference:

Journal of Geophysical Research: Space Physics, doi:10.1002/2016JA022715, 2016

Atmospheric oxygen levels have declined over the past 1 million years, although not nearly enough to trigger any major problems for life on Earth, a new study finds.

The research behind this new finding could help shed light on what controls atmospheric oxygen levels over long spans of time, the researchers said.

Atmospheric oxygen levels are fundamentally linked to the evolution of life on Earth, as well as changes in geochemical cycles related to climate variations. As such, scientists have long sought to reconstruct how atmospheric oxygen levels fluctuated in the past, and what might control these shifts.

However, models of past atmospheric oxygen levels often markedly disagree, differing by as much as about 20 percent of Earth's atmosphere, which is oxygen's present-day concentration, the researchers said. 1 It is not even known if atmospheric oxygen levels varied or remained steady over the past 1 million years.

"There was no consensus on whether the oxygen cycle before humankind began burning fossil fuels was in or out of balance and, if so, whether it was increasing or decreasing," said study lead author Daniel Stolper, a geochemistat Princeton University in New Jersey.

In the new study, researchers calculated past atmospheric oxygen levels by looking at air trapped inside ancient polar ice samples. Specifically, they looked at samples from Greenland and Antarctica.

The new estimates suggest that atmospheric oxygen levels have fallen by 0.7 percent over the past 800,000 years. The scientists concluded that oxygen sinks — processes that removed oxygen from the air — were about 1.7 percent larger than oxygen sources during this time.

Although a drop in atmospheric oxygen levels might sound alarming, the decrease the researchers found "is trivial in regard to ecosystems," Stolper told Live Science. "To put it in perspective, the pressure in the atmosphere declines with elevation. A 0.7 percent decline in the atmospheric pressure of oxygen occurs at about 100 meters (330 feet) above sea level — that is, about the 30th floor of a tall building."

There are two hypotheses that may help explain this oxygen decline over the past million years, Stolper said.

An international team of astronomers led by Hsing-Wen Lin of the National Central University in Taiwan has detected five new so-called "Neptune trojans" - minor bodies sharing the same orbit as the planet Neptune. The discovery was made by the Pan-STARRS 1 (PS1) survey and is described in a paper published Sept. 15 on arXiv.org.

The PS1 survey, which utilizes the first Pan-STARRS (Panoramic Survey Telescope and Rapid Response System) telescope in Hawaii, designated PS1, is one of the best tools to search for Neptune trojans. The survey, lasting from May 2010 to May 2014, has made a strong contribution to knowledge of the solar system's minor bodies due to its very wide survey area and its optimized cadence for searching moving objects.

"PS1 survey has a very wide survey area that is deep enough to cover a large part of the Neptune trojan cloud. PS1 currently is the only one with the capability to detect several Neptune trojans in a single survey," Lin told Phys.org.

The researchers found four new L4 trojans, meaning that they orbit Neptune's L4 Lagrangian point 60 degrees ahead of Neptune; they also found one L5 trojan - orbiting the L5 region 60 degrees behind the planet. The newly detected objects have sizes ranging from 100 to 200 kilometers in diameter.

What drew the attention of the astronomers is the fact that the new L5 trojan is dynamically more unstable than the other four, indicating that it could be temporarily captured into the Neptune trojan cloud.

On September 18, 2016, Frankie Lucena of Cabo Rojo, Puerto Rico, photographed an enormous 'A-bomb' sprite over the Caribbean Sea. These rank as the largest type of sprite in both horizontal and vertical dimensions. And for a split-second, the sky lit up like this:

This type of sprite is often called 'jellyfish' or 'A-bomb,' and ranks as the largest type of sprite in both horizontal and vertical dimensions.

It consists of a bright halo approximately 85 km above Earth's surface surrounding sprite elements with long tendrils reaching down as low as ~30 km above ground level.

This kind of sprite tends to be triggered by a very impulsive positive cloud-to-ground flash.

But curiously, Lucena did not observe an instigating lightning bolt, but, Instead, just before the sprite appeared, he recorded a bright point-like flash of light. Was it a cosmic ray hitting the camera?.

A jealous Planet Nine may have shoved its siblings for attention. If a massive ninth planet exists in our solar system, it might explain why the planets are out of line with the sun.

The eight major planets still circle the sun in the original plane of their birth. The sun rotates on its own axis, but surprisingly, that spin is tilted: the axis lies at an angle of 6 degrees relative to a line perpendicular to the plane of the planets.

There are a few theories to explain this jaunty slant, including the temporary tug of a passing star aeons ago, or interactions between the magnetic fields of the sun and the primordial dusty disc that formed the solar system. But it is hard to account for why the sun's spin is aligned the way it is relative to the planets.

Two teams of astronomers have just announced a new explanation: a hypothetical massive planet in the outer solar system could be interfering with all the other planets' orbits.

What caused this mysterious blue streak across Houston's morning sky? Meteorologist Travis Herzog says this is a thunderstorm cloud shadow illuminated by crepuscular rays.

These cloud shadows were formed by tropical showers below the horizon in the Gulf near Louisiana. They were visible all the way to New Braunfels and south Texas.