The Voyager-1 spacecraft has become the first manmade object to leave the Solar System.

Scientists say the probe's instruments indicate it has moved beyond the bubble of hot gas from our Sun and is now moving in the space between the stars.

Launched in 1977, Voyager was sent initially to study the outer planets, but then just kept on going.

Today, the veteran Nasa mission is almost 19 billion km (12 billion miles) from home.

This distance is so vast that it takes 17 hours now for a radio signal sent from Voyager to reach receivers here on Earth.

A Danish group that has reproduced the Earth's atmosphere in the laboratory has shown how clouds might be seeded by incoming cosmic rays. The team believes that the research provides evidence that fluctuations in the cosmic-ray flux caused by changes in solar activity could play a role in climate change. Other climate researchers, however, remain sceptical of the link between cosmic rays and climate.

The conventional view of climate scientists, as expressed in the 2007 report of the Intergovernmental Panel on Climate Change, is that most of the warming of the Earth's surface over the last few decades is down to the atmospheric build-up of manmade greenhouse gases such as carbon dioxide. But Henrik Svensmark of the National Space Institute in Denmark believes that an effect related to the Sun's fluctuating magnetic fields may also play a major role in the warming.

For well over a decade Svensmark has studied how the energetic particles reaching Earth from deep space, known as cosmic rays, can influence the planet's climate as a result of changes to the Sun's output. The idea is that cosmic rays seed clouds by ionizing molecules in Earth's atmosphere that draw in other molecules to create the aerosols around which water vapour can condense to form cloud droplets. The low-lying clouds that result then have the effect of cooling the Earth by reflecting incoming sunshine back out to space. Since the Sun's magnetic field tends to deflect cosmic rays away from the Earth, the planet will be warmer when solar activity is high and, conversely, cooler when it is low.

We often think of human cells as tiny computers that perform assigned tasks, where disease is a result of a malfunction. But in the current issue of Science, researchers at The Mount Sinai Medical Center offer a radical view of health - seeing it more as a cooperative state among cells, while they see disease as result of cells at war that fight with each other for domination.

Their unique approach is backed by experimental evidence. The researchers show a network of genes in cells, which includes the powerful tumor suppressor p53, which enforce a cooperative state within cells - rather like the queen bee in a beehive. Disease or disorder occurs when these enforcer genes are mutated, allowing competition between cells to ensue.

"Both competition and cooperation drive evolution, and we are wired for cooperation all the way down to our genes," says the study's senior investigator, Thomas P. Zwaka, MD, PhD, Professor at the Black Family Stem Cell Institute at the Icahn School of Medicine at Mount Sinai.

The findings, if backed by future research, offer a new way to address disease, Dr. Zwaka says. Understanding the genetic basis of cooperative and competitive cellular behaviors could explain how cancer and immune system dysfunction develops, he says. "If a cell has lost a gene that fosters communication among cells, it may dominate other cells by ignoring signals to stop proliferating. It also makes sense that the immune system might detect and attack cells that are not cooperating. Failure to cooperate may also underlie development of birth defects."

He adds that it may be possible to flip the cooperation switch back on therapeutically, or to manipulate stem-like cells to misbehave in a way that produces replacement cells for regenerative medicine.

"Cell misbehave, they are unpredictable. They do not operate like little machines," he says. "What our study suggests is that cooperation is so central to our evolution that we have genetic mechanisms to protect us against cheating and dominating behavior."

A veteran NASA comet-chasing probe has stopped communicating with mission managers and is apparently spinning out of control.

The robotic spacecraft, that was sent to Comet Tempel 1 to carry out a historic bombing run with a washing machine-sized 370 kilogram (820 lb) impactor on July 4, 2005, was originally called Deep Impact, but had its mission extended to continue solar system exploration after its cometary encounter and renamed Extrasolar Planet Observation and Deep Impact Extended Investigation, or EPOXI. Scientists of the University of Maryland manages the EPOXI mission.

After the 2005 comet encounter, EPOXI completed an Earth flyby and was sent to travel past another icy body, Comet Hartley 2, in 2010, recovering high resolution images of the comet's nucleus. The mission was then tasked with another, more distant, observation of Comet Garradd in 2012. Most recently, the spacecraft was commanded to track the incoming Comet ISON, recovering the first images in January. In 2008, a component of the EPOXI mission (called the Extrasolar Planet Observation and Characterization, or EPOCh) was also used to characterize observations of previously discovered extrasolar planets orbiting other stars.

But it seems that the EPOXI mission may have come to an end.

Did a meteor trigger the beginnings of civilisation? Scientists find 'conclusive proof' that meteor impact caused humans to develop agriculture

• Evidence suggests a meteor or asteroid struck Quebec 12,900 years ago

• This impact caused a change in climate that made Earth colder and drier

• Larger animals died out and humans began eating berries and cereals

• An increase in agriculture and communities led to modern-day civilisation

A cataclysmic meteor impact in Canada that is linked to the death of many animals, including the woolly mammoth, may have also been the catalyst that triggered the start of civilisation as we know it, claims new research.

Evidence suggests a meteor struck Quebec around 12,900 years ago and scientists believe this impact caused the Earth's climate to become colder and drier - known as the Younger Dryas period.

Why did mammoths, mastodons, and other mega-beasts vanish from North America?

Was it because:

1) humans killed them;

2) they couldn't hack the climate after the Ice Age ended; or

3) an exploding comet ignited continent-wide wildfires, sent hundred-mile-an-hour winds and tornadoes howling across the land, and shattered the North American ice sheet, while also maybe gouging out the Great Lakes?

Let's talk about option number three.

The idea that a comet struck Earth 12,900 years ago, at the beginning of a strange interlude of climate cooling called the Younger Dryas was first proposed in 2007.

In the bitter scientific debate that has flared sporadically ever since, the latest evidence includes:

- Tiny, glassy "spherules" of rock found in a Pennsylvania flowerbed by a woman who had seen a NOVA program about the comet hypothesis. In a paper that got wide coverage last week, Dartmouth researchers argue that those spherules were hurled to Pennsylvania by an impact in Quebec 12,900 years ago.

- Traces of platinum deposited on the Greenland ice cap at about the same time. Harvard researchers argue that the platinum probably came from an extraterrestrial object - not a comet, however, but a rare type of iron-rich meteorite.

- Spherules in Syria. In their latest paper, some of the original proponents of the impact hypothesis now say it deposited 10 million metric tons of spherules over an area of 20 million square miles, stretching from Syria through Europe to the west coast of North America.

Many are anticipating the brightening of Comet ISON, which is now in Earth's predawn sky, not far from the bright planets Jupiter and Mars, but too faint to see without telescopes and/or photographic equipment. Read more about Comet ISON here. In the meantime, on September 9, 2013, noted comet discoverer Terry Lovejoy of Australia announced another new comet, bringing his total number of comet discoveries to four. The newest Comet Lovejoy will be in the same part of the sky as Comet ISON beginning in November. What a cool photo opportunity!

The new comet has been formally labeled as C/2013 R1 Lovejoy. Terry Lovejoy apparently used a relatively small 8-inch (20 cm) Schmidt-Cassegrain reflecting telescope to photograph the new comet for two nights, as this faint object was located on the sky's dome in front of the border between our constellations Orion and Monoceros.

Read Terry Lovejoy's own discovery story here.

Now that the comet has been confirmed by other astronomers, amateur astronomers will be getting excited! Watch this space.

Washington - New research suggests it might be possible to spot early signs of multiple sclerosis in patients' spinal fluid, findings that offer a new clue about how this mysterious disease forms.

The study released Tuesday was small and must be verified by additional research. But if it pans out, the finding suggests scientists should take a closer look at a different part of the brain than is usually linked to MS.

"It really tells us that MS may be affecting more parts of the brain much earlier than we anticipated," said Timothy Coetzee, chief research officer at the National MS Society. Coetzee wasn't involved with the new study.

Multiple sclerosis is a neurological disease that causes varying symptoms - numbness and tingling in one person, impaired walking and vision loss in another - that often wax and wane.

There are treatments but no cure. Doctors don't know what causes MS, just that it occurs when the protective insulation, called myelin, that coats nerve fibers is gradually destroyed, leaving behind tough scar tissue. That short-circuits messages from the brain and spinal cord to the rest of the body.

But because brain scans can have trouble spotting early damage, it's hard to tell whether someone experiencing initial symptoms really is developing MS and thus should start treatment.

For 30 years, a large near-Earth asteroid wandered its lone, intrepid path, passing before the scrutinizing eyes of scientists armed with telescopes while keeping something to itself. The object, known as Don Quixote, whose journey stretches to the orbit of Jupiter, now appears to be a comet.

The discovery resulted from an ongoing project coordinated by researchers at Northern Arizona University, Flagstaff, Ariz., using NASA's Spitzer Space Telescope. Through a lot of focused attention and a little luck, they found evidence of comet activity, which had evaded detection for three decades.

The results show that Don Quixote is not, in fact, a dead comet, as previously believed, but it has a faint coma and tail. In fact, this object, the third-biggest near-Earth asteroid known, skirts Earth with an erratic, extended orbit and is "sopping wet," said David Trilling of Northern Arizona University, with large deposits of carbon dioxide and presumably water ice. Don Quixote is about 11 miles (18 kilometers) long.

Unexplained satellite movements in orbit, secretive payloads, testing of potential anti-satellite technologies and no official explanation - this sounds like the plot of the next James Bond adventure. But this is no 007 movie, this is the storyline of several Chinese satellites that are raising eyebrows in the West.

As reported by veteran space correspondent Leonard David at SPACE.com, no one really knows what China is up to and this has led to speculation in space analyst circles.

The speculation is focused on the satellites Shiyan-7, Chuangxin-3 and Shijian-15, all of which were launched on the same Long March 4C (CZ-4C) rocket on July 20 (pictured top).

The official word was that the trio carried science payloads. Nothing too strange with that. But then Shiyan-7 (also known as SY-7, or Experiment 7) recently carried out a series of maneuvers with Chuangxin-3 (CX-3) only for it to make a sudden course change to rendezvous with an older satellite, Shijian 7 (SJ-7, Practice 7), which was launched in 2005.