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In comparison, the sun varies in the amount of light it emits by only 0.1 percent over the course of a relatively stable 11-year-long pattern known as the solar cycle.

"the light reaching the top of the Earth's atmosphere provides about 2,500 times as much energy as the total of all other sources combined,"

even 0.1 percent of the amount of light the sun emits exceeds all other energy sources the Earth's atmosphere sees combined, such as the radioactivity naturally emitted from Earth's core,

Many of the ways the scientists proposed these fluctuations in solar activity could influence Earth were complicated in nature.

, solar energetic particles and cosmic rays could reduce ozone levels in the stratosphere

in turn alters the behavior of the atmosphere below it, perhaps even pushing storms on the surface off cours

"In the lower stratosphere, the presence of ozone causes a local warming because of the breakup of ozone molecules by ultraviolet light,

When the ozone is removed, "the stratosphere there becomes cooler, increasing the temperature contrast between the tropics and the polar region

contrast in temperatures in the stratosphere and the upper troposphere leads to instabilities in the atmospheric flow west to east.

feed the strength of jet streams, ultimately altering flows in the upper troposphere, the layer of atmosphere closest to Earth's surface.

alter the distribution of storms over the middle latitudes

the sun might have a role to play in this kind of process. I would have to say this would be a very difficult mechanism to prove in climate models

climate scientist Gerald Meehl at the National Center for Atmospheric Research and his colleagues suggest that solar variability is leaving a definite imprint on climate, especially in the Pacific Ocean.

When researchers look at sea surface temperature data during sunspot peak years, the tropical Pacific showed a pattern very much like that expected with La Niña,

cyclical cooling of the Pacific Ocean that regularly affects climate worldwide, with sunspot peak years leading to a cooling of almost 1 degree Celsius (1.8 degrees Fahrenheit) in the equatorial eastern Pacific

peaks in the sunspot cycle were linked with increased precipitation in a number of areas across the globe, as well as above-normal sea-level pressure in the mid-latitude North and South Pacific.

Scientists have also often speculated whether the Maunder Minimum, a 70-year dearth of sunspots in the late 17th to early 18th century, was linked with the coldest part of the Little Ice Age, during which Europe and North America experienced bitterly cold winter

This regional cooling might be linked with a drop in the sun's extreme ultraviolet radiation.

t, the sun could currently be on the cusp of a miniature version of the Maunder Minimum, since the current solar cycle is the weakest in more than 50 years.

Although the sun is the main source of heat for Earth, the researchers note that solar variability may have more of a regional effect than a global one

While the sun is by far the dominant energy source powering our climate system, do not assume that it is causing much of recent climate changes. It's pretty stabl

Ancient signals of climate such as tree rings and ice cores might also help shed light on the link between the sun and climate

Since variations in Earth's magnetic field and atmospheric circulation might disrupt this evidence on Earth,

a better long-term record of solar radiation might lie in the rocks and sediments of the moon or Mar

a new study also points to a more earthbound culprit: the presence of a land bridge connecting Asia to North America.

debated whether the climate swings were driven by sharp variations in solar activity or simply by unstable climatic processes

Earth's climate has been relatively stable since the end of the last ice age

temperatures were fairly stable, too, after the ice age began in earnest about 100,000 years ago

20,000 years later, things became unhinged

global sea level dropped to about 50 meters lower than it is today

As the ice sheets that covered North America and northern Eurasia snatched up more and more of Earth's water

exposed a broad strip of land that connected what is today Alaska and Siberia

Ancient animals used the land bridge, which measured as much as 1500 kilometers wide in spots, to roam back and forth between Asia and North America

also huge consequences for Earth's climate

two sets of climate simulations

one in which the Bering Strait was open

one in which it was blocked

each set of simulations, the researchers gradually added large amounts of fresh water to the North Atlantic between the latitudes of 20° and 50

researchers propose, this swath, which spans the latitudes from southern Cuba to southern England, would have received large amounts of meltwater from Northern Hemisphere ice sheets during warm spells that occasionally punctuated the ice age

Today, the surface waters in this swath affect the temperature and salinity of water even farther north in the Atlantic

a region where surface waters cool, sink to the seafloor, and then flow southward—a critical link of the worldwide conveyor belt of ocean circulatio

Gulf Stream, which brings climate-warming waters from the equator to the North Atlantic, comes to a halt.

If waters of the far North Atlantic don't sink, says Hu, much of the large-scale ocean circulation worldwide temporarily collapses

surface waters became so fresh that they never got denser than the underlying salty water, and therefore never sank

shutting down ocean circulation and plunging areas around the North Atlantic, including Greenland, into a cold spell

researchers noted a critical difference between the sets of simulations: When the Bering Strait was closed, it took as many as 1400 years for ocean circulation to recover; when the strait was open, the circulation rarely took more than 400 years to recuperate

sign that ocean circulation is stable when the strait is open

Whenever the ocean circulation shut down in the simulations, temperatures in Greenland suddenly dropped by 12°C—a decrease similar in magnitude to many abrupt cold snaps chronicled in the Greenland ice core records

imagery shows that glaciers in the region were melting even faster in the 1930s than they are today

A brief cooling period starting in the mid-20th century allowed new ice to form, and then the melting began to accelerate again in the 2000s.

we now have a detailed historical analogue for more recent glacier loss

confirmed that glaciers are very sensitive indicators of climate."

cleaning up in the basement and had found some old glass plates with glaciers on them

The reason the plates were forgotten was that they were recorded for mapping, and once the map was produced they didn't have much value."

They contained aerial photographs of land, sea and glaciers in the southeast region of the country, along with travel photos of Rasmussen's team.

researchers digitized all the old images and used software to look for differences in the shape of the southeast Greenland coastline where the ice meets the Atlantic Ocean

calculated the distance the ice front moved in each time period.

Over the 80 years, two events stand out: glacial retreats from 1933-1934 and 2000-2010

1930s, fewer glaciers were melting than are today, and most of those that were melting were land-terminating glaciers, meaning that they did not contact the sea.

were melting retreated an average of 20 meters per year - the fastest retreating at 374 meters per year

Fifty-five percent of the glaciers in the study had similar or higher retreat rates during the 1930s than they do today.

more glaciers in southeast Greenland are retreating today, and the average ice loss is 50 meters per year. That's because a few glaciers with very fast melting rates - including one retreating at 887 meters per year - boost the overall average.

From 1943-1972, southeast Greenland cooled - probably due to sulfur pollution, which reflects sunlight away from the earth.

Sulfur dioxide is a poisonous gas produced by volcanoes and industrial processes. It has been tied to serious health problems and death, and is also the main ingredient in acid rain.

deadly pollution caused the climate to cool, but rather that the brief cooling allowed researchers to see how Greenland ice responded to the changing climate.

glaciers responded to the cooling more rapidly than researchers had seen in earlier studies

Sixty percent of the glaciers advanced during that time, while 12 percent were stationary

now that the warming has resumed, the glacial retreat is dominated by marine-terminating outlet glaciers, the melting of which contributes to sea level rise.

we see that the mid-century cooling stabilized the glaciers," Box said. "That suggests that if we want to stabilize today's accelerating ice loss, we need to see a little cooling of our own."

MAVEN arrives about 48 hours ahead of MOM on September 21, 2014.

rendezvous on September 24, 2014

MOM probe

will study the atmosphere and sniff for signals of methane.

Working together, MOM and MAVEN will revolutionize our understanding of Mars atmosphere, dramatic climatic history and potential for habitability

MOM was designed and developed by the Indian Space Research Organization’s (ISRO) at a cost of $69 Million and marks India’s maiden foray into interplanetary flight

before reaching Mars, mission navigators must keep the craft

on course

from Earth to Mars through a series of in flight Trajectory Correction Maneuvers (TMSs).

The second TCM was just successfully performed on June 11 by firing the spacecraft’s 22 Newton thrusters for a duration of 16 seconds

TCM-1 was conducted on December 11, 2013 by firing the 22 Newton Thrusters for 40.5 seconds

Two additional TCM firings are planned in August and September 2014.

the probe has flown about 70% of the way to Mars, traveling about 466 million kilometers out of a total of 680 million kilometers (400 million miles) overall, with about 95 days to go.

One way radio signals to Earth take approximately 340 seconds

ISRO reports the spacecraft and its five science instruments are healthy. It is being continuously monitored by the Indian Deep Space Network (IDSN) and NASA JPL’s Deep Space Network (DSN). Remove this ad

Although they were developed independently and have different suites of scientific instruments, the MAVEN and MOM science teams will “work together” to unlock the secrets of Mars atmosphere and climate history, MAVEN’s top scientist

MAVEN’s principal Investigator

“We have had some discussions with their science team, and there are some overlapping objectives,”

“At the point where we [MAVEN and MOM] are both in orbit collecting data we do plan to collaborate and work together with the data jointly,”

the estimated 7-Earth-mass exoplanet receives around 62-67% of the radiation that Earth gets from the Sun

HD 40307 g is still a candidate

observations are needed to not only confirm its existence but also to find out exactly what kind of planet it may be

findings demonstrate that Mars' atmosphere, though just 1 percent as thick as that of Earth, does provide a significant amount of shielding

lacks a magnetic field, which gives our planet another layer of protection.)

Radiation at the Martian surface is about half as high as the levels Curiosity experienced during its nine-month cruise through deep space

findings are preliminary, as Curiosity is just three months into a planned two-year prime mission

team have not yet put hard numbers on the Martian radiation levels

hoping to release that at the

American Geophysical Union's huge conference in San Francisco

from Dec. 3-7. "

One key to understanding the big picture will be documenting the effects of big solar storms, which can blast huge clouds of charged particles into space

Curiosity flew through one such cloud on its way to Mars but has yet to experience one on the surface

More than 38,000 meteorites have been found in Antarctica, but only 30 bigger than 40 pounds (18 kg).

The Russian meteor that burst into fragments above the Chelyabinsk region on Feb. 15 is also an ordinary chondrite

charred black crust stands out

in the

snow, and the cold, dry climate helps preserve any organic chemicals inside the rocks

The expedition collected 425 meteorites in 40 days, with a total weight of 165 pounds (75 kg).

they may have found one Mars meteorite and one piece of the asteroid Vesta among the many discoveries.

A team from Belgium and Japan discovered the

meteorite as the members drove across the East Antarctic plateau on snowmobiles

known as Northwest Africa (NWA) 7034, is the second-oldest of 110 named stones originating from Mars that have been retrieved on Earth

Purchased from a Moroccan meteorite dealer in 2011, the black, baseball-sized stone, which weighs less than 1 pound, is 2.1 billon years old, meaning it formed during what is known as the early Amazonian era in Mars' geologic history.

The only older Mars meteorite found so far is the 4-billion-year-old Allan Hills 84001 Antarctica stone that was the source of speculation about microfossils in 1996

Early Mars was believed to be warm and wet, but the planet lost most of its atmosphere and its surface water to become a cold, dry desert that appears today

The time from when our meteorite is from is maybe a transitional period in the climate, when Mars was losing its atmosphere, losing its water on the surface

relatively rich in water -- about 6,000 parts per million -- compared with typical Martian meteorites that contain about 200- to 300 parts per million

similar to basaltic rocks on Earth that form in volcanic eruptions

NWA 7034, nicknamed "Black Beauty," also contains tiny bits of carbon, formed from geologic, not biological activity

Scientists don't know why more meteorites like Black Beauty haven't been found on Earth. The period of time from which they originated may be relatively short, or most may not survive the trip through Earth's atmosphere

This one does look completely different," he added. "It's jet black. The others are slightly greenish cast

After an initial battery of tests revealed the rock's unique nature, meteorite hunters returned to the area where it was found to search for other similar stones

took several months to get an idea of what it was

eventually realized there was no other conclusion but that it was Martian and that it was different from all the other ones

If it were similar, we would have known within one day," he added

Four more pieces, all smaller than the original, have now been found

Paint doesn't preserve well in the rain forest climate of Guatemala, and Saturno figured that the faint red and black lines his student had found weren't going to yield much information

The discovery was "certainly nothing to write home about

felt he had a responsibility to excavate the room the looters had tried to reach, if only to be able to report the size of the structure along with the paint finding.

shocked to run into a brilliantly painted portrait: a Mayan king, sitting on his throne, wearing a red crown with blue feathers flowing out behind him.

Another figure peeks out from behind him

On an adjoining wall, three loincloth-clad figures sit, wearing feathered headdresses

ext to the king, a man painted in brilliant orange wearing jade bracelets reaches out with a stylus, likely identifying him as a scribe. He is labeled as "Younger Brother Obsidian," or perhaps "Junior Obsidian

small, 6-foot-by-6-foot room

calendar seemed to have been added after the murals were completed

almost as if an ancient scribe got sick of flipping through a document to find his timekeeping chart and decided to put it on the wall for at-a-glance reference

captioned "Older Brother Obsidian," or "Senior Obsidian,"

calendar also appears to note the cycles of Mars and Venus,

Most likely

the wall calendar and the Dresden Codex both arose from earlier books that long ago rotted away

The murals only survived, because, instead of collapsing the room, Mayan engineers filled it with rubble and then built on top of it.

This is clearly a space where someone important was living, this important household of the noble class, and here you also have a mathematician working in that space," Stuart said. "It's a great illustration of how closely those roles were connected in Mayan society

Unfortunately, the name of the king pictured in the mural room has been lost.

Xultun was first discovered in 1915, less than 0.1 percent has been explored

Looters damaged much of the ancient city in the 1970s

much of historical significance has been lost. But archaeologists still don't even know how far the boundaries of the town extend.

Based on the shapes of the jaw and skull bones found in the fossils, the team concluded that the three animals belonged to the same species and were tyrannosaurs

broader classification of two-legged meat-eaters called theropods

biggest of the newly described creatures — the largest extensively feathered dino known to date — was about one-quarter the weight of its relative, Tyrannosaurus rex

smaller dinosaur is named Yutyrannus hauli, which translates to “beautiful feathered tyrant

new species had feathers that were at least 15 centimeters long and look as if they covered the dinosaur’s skin

might have given the dinosaur a shaggy appearance

the full extent of this covering is difficult to confirm because the specimens aren’t complete.

For the vast majority of dinosaurs we only have bone. We don’t have feathers or featherless skin

Full-feathered dinosaurs that have been discovered so far have been much smaller

much more likely to lose body heat because of their size

scientists thought these petite creatures used a fluffy layer to stay warm

study authors think that the newfound dinos might have also needed some insulation

But Norell is not convinced

Many large animals that live in warm climates, such as modern giraffes and wildebeests, have external covering but don’t need it for insulation, he says.

feathers might also have helped the dinosaurs show off and attract mates.

Other traits the new dinos had include a high, bumpy nose plate, known as a midline crest

unclear what type of posture the animals maintained, Sullivan estimates that the full-grown dino stood about 2.5 meters tall.

pressurized enclosure extends over Enterprise's tail, which tops out at 57 feet (17 meters) high, and beyond the shuttle's 78-foot (24-meter) wingspan. It occupies the rear of the Intrepid's flight deck with the shuttle's nose pointed out toward the Hudson River

display is set to open to the public on July 19

visitors the chance to closely view and circle around the prototype winged orbiter

The location for the permanent Enterprise exhibit is still to be decided. Intrepid officials told collectSPACE that they are considering locations across the street from where the aircraft carrier is docked and also alongside the museum on the pier.

also has additional color calibration tools for the rover’s Mastcam

; in addition to the words “Mars 2012″ and “To Mars, To Explore” around its top bezel,

along its edge

Along with line drawings and the word for “Mars” in sixteen languages, Curiosity’s sundial bears the following inscription

“For millennia, Mars has stimulated our imaginations. First, we saw Mars as a wandering star, a bringer of war from the abode of the gods. In recent centuries, the planet’s changing appearance in telescopes caused us to think that Mars had a climate like the Earth’s. Our first space age views revealed only a cratered, Moon-like world, but later missions showed that Mars once had abundant liquid water. Through it all, we have wondered: Has there been life on Mars? To those taking the next steps to find out, we wish a safe journey and the joy of discovery.”

Receipt

Initial sponsors include Byte Internet (a Dutch Internet/Webhosting provider); Dutch lawfirm VBC Notarissen; Dutch consulting company MeetIn; New-Energy.tv (an independent Dutch web station that focuses on energy and climate); and Dejan SEO (an Australia-based search engine optimization firm). [

Mars One aims to launch a series of robotic missions between 2016 and 2020 that will build a habitable outpost on the Red Planet. The first four astronauts will set foot on Mars in 2023, and more will arrive every two years after that. There are no plans to return these pioneers to Earth.

Mars One estimates that it will cost about $6 billion to put the first four humans on the Red Planet

hopes the "Big Brother"-style reality show will pay most of these costs

televised action is slated to begin in 2013, when Mars One begins the process of selecting its 40-person astronaut corps

snow on Mars fell from clouds around the planet's south pole during the Martian winter spanning 2006 and 2007

The Martian south pole hosts a frozen carbon dioxide — or "dry ice" — cap year-round

new discovery may help explain how it formed and persists, researchers

the first definitive detections of carbon-dioxide snow clouds

"We firmly establish the clouds are composed of carbon dioxide — flakes of Martian air — and they are thick enough to result in snowfall accumulation at the surface.

find means Mars hosts two different kinds of snowfall

In 2008, NASA's Phoenix lander observed water-ice snow

near the Red Planet's north pole

studied data gathered by MRO's Mars Climate Sounder instrument during the Red Planet's southern winter in 2006-2007

instrument measures brightness in nine different wavelengths of visible and infrared light, allowing scientists to learn key characteristics of the particles and gases in the Martian atmosphere, such as their sizes and concentrations.

one behemoth 300 miles (500 kilometers) wide

One line of evidence for snow is that the carbon-dioxide ice particles in the clouds are large enough to fall to the ground during the lifespan of the clouds

Another comes from observations when the instrument is pointed toward the horizon

"The infrared spectra signature of the clouds viewed from this angle is clearly carbon-dioxide ice particles, and they extend to the surface

"The finding of snowfall could mean that the type of deposition — snow or frost — is somehow linked to the year-to-year preservation of the residual ca

Dry ice requires temperatures of about minus 193 degrees Fahrenheit (minus 125 Celsius) to fall, reinforcing just how cold the Martian surface is.

Astronomers still aren't entirely sure how the dry ice sustaining Mars' south polar cap — the only place where frozen carbon dioxide exists year-round on the planet's surface — is deposited. It could come from snowfall, or the stuff may freeze out of the air at ground level, researchers said.

It will take the spacecraft 10 months to reach the Red Planet, with arrival scheduled for Sept. 22, 2014

MAVEN’s purpose is to accomplish world class science after arriving at Mars and completing a check-out period before it can finally begin collecting science data

MAVEN will answer key questions about the evolution of Mars, its geology and the potential for the evolution of life

Mars was once wet billions of years ago,

Now it’s a cold arid world, not

hospitable to life

want to determine what were the drivers of that change

What is the history of Martian habitability, climate change and the potential for life

MAVEN will study Mars upper atmosphere to explore how the Red Planet may have lost its atmosphere over billions of years

It will measure current rates of atmospheric loss to determine how and when Mars lost its atmosphere and water

The MAVEN probe carries nine sensors in three instrument suites

The Particles and Fields Package,

contains six instruments to characterize the solar wind and the ionosphere of Mars.

The Remote Sensing Package,

will determine global characteristics of the upper atmosphere and ionosphere.

The Neutral Gas and Ion Mass Spectrometer,

will measure the composition of Mars’ upper atmosphere.

Over the course of its one-Earth-year primary mission, MAVEN will observe all of Mars’ latitudes at altitudes ranging from 93 miles to more than 3,800 miles.

MAVEN will execute five deep dip maneuvers during the first year, descending to an altitude of 78 miles. This marks the lower boundary of the planet’s upper atmosphere.