Researchers at the University of Toronto have discovered a new greenhouse gas that has the highest impact on global warming to date.

Best Meteor Shower of the Year Peaks Tonight: How to Watch

One of the best meteor showers of the year is set to put on a performance Friday night, but if you can't catch the cosmic display in person, you can watch it live online.
The Geminid meteor shower — named for the constellation Gemini — is peaking late tonight into Saturday morning, potentially treating stargazers in light-free areas to about 90 to 120 meteors per hour. Observers can expect to get the best views of the shower, weather permitting, at around 4 a.m. local time in the wee hours of Saturday morning after the waxing moon sets, according to Bill Cooke, head of NASA's Meteoroid Environment Office.
"This year, there will be a magic hour starting at about 4 a.m. up until dawn that there will be no moon and you'll be able to see the Geminids in their full glory," Cooke told reporters on Dec. 11. Space fans everywhere can catch the meteor show live online through two webcasts from the online Slooh Space Camera and NASA. You can watch both NASA and Slooh's live webcasts on SPACE.com.
NASA is hosting a Web chat about the meteor shower beginning at 11 p.m. EST. Cooke and two of his team members — Danielle Moser and Rhiannon Blaauw — will answer questions from the public about the Geminids during the "up all night" webcast. The chat is expected to run until 3 a.m. EST and can be seen here: http://www.nasa.gov/connect/chat/geminids_2013a.html#.Uqr4FIZQGSo

Slooh will provide a free live feed of the Geminids from an observatory on the Canary Islands starting at 5:30 p.m. EST and running into the night, ending at 1 a.m. EST. You can watch the webcast directly at www.slooh.com or by using the space camera's iPad app.

Geminid meteors appear to radiate from the constellation Gemini and have a reputation for being bright and slow. The shower can also produce brilliant fireballs that streak through the sky.

"The best thing to do to observe meteors is to lie flat on your back and look straight up," Cooke said. "You don't want to look at Gemini, you just want to look straight up and take in as much of the sky as possible because meteors can appear anywhere in the sky and the more sky you see, the better you chance of seeing a meteor."

Meteor showers are created when Earth passes through streams of debris left behind by asteroids or comets. Pieces of space rock and dust are in space are called meteoroids and they become meteors when they burn up in the atmosphere. Meteorites are pieces of meteors that make it to Earth's surface.

The Geminid shower happens every year when Earth passes through the trail of debris left behind the asteroid 3200 Phaethon. The meteor display was first officially detected in the 1800s when the peak was marked by only 20 meteors per hour.

World's Smallest Pacemaker Can Be Implanted Without Surgery

Pacemaker surgery typically requires a doctor to make an incision above a patient’s heart, dig a cavity into which they can implant the heartbeat-regulating device, and then connect the pulse generator to wires delivered through a vein near the collarbone. Such surgery could soon be completely unnecessary. Instead, doctors could employ miniaturized wireless pacemakers that can be delivered into the heart through a major vein in the thigh.
On Monday, doctors in Austria implanted one such device into a patient — the first participant in a human trial of what device-manufacturer Medtronic says is the smallest pacemaker in the world. The device is 24 millimeters long and 0.75 cubic centimeters in volume — a tenth the size of a conventional pacemaker. Earlier this year, another device manufacturer, St. Jude Medical, bought a startup called Nanostim that makes another tiny pacemaker, and St. Jude is offering it to patients in Europe. This device is 41 millimeters long and one cubic centimeter in volume.

Doctors can implant such pacemakers into the heart through blood vessels, via an incision in the thigh. They use steerable, flexible tubes called catheters to push the pacemakers through a large vein.
The two new devices are the latest effort to make heart surgery less traumatic. Doctors began to widely use less invasive heart treatments in the late 1990s, when artery-unclogging balloons delivered by catheters started to replace bypass surgeries. Other cardiac technologies like stents, which prop open weak or narrow arteries, can also be delivered through blood vessels. More recently, researchers have developed artificial valves for patients whose natural valves have become damaged; these devices can also be delivered by catheters snaking through large blood vessels.
Brian Lindman, a cardiovascular specialist at Washington University School of Medicine, and colleagues have found that less invasive catheter-based procedures for valve repair can be safer for high-risk elderly patients and can enable doctors to treat patients who are too frail to undergo surgery. More recently, Lindman published a study suggesting that the transcatheter method may improve the odds of survival for diabetic patients as well. However, for some cardiac treatments such as valve repair, a more invasive surgery enables longer-lasting repairs, and so may be the better option for patients strong enough for surgery. “Surgery or transcatheter is not always better,” says Lindman. “It depends on the cardiac problem and on the nuances of each procedure.”
Both tiny pacemakers are now being tested in human trials, and St. Jude’s has been approved for use in patients in Europe. The device manufacturers say the batteries in the tiny pacemakers will last up to eight or 10 years when running at full-stimulating capacity. The new pacemakers are also “leadless” — that is, they don’t require long electrodes winding their way into heart. Instead, they sit inside the heart and deliver electric pulses through small prongs that touch the heart.

This new design reduces the amount of power required by the device and eliminates a major source of device failure.

This new design reduces the amount of power required by the device and eliminates a major source of device failure.
Medtronic has also developed a miniaturized cardiac monitor for patients with arrhythmias or undiagnosed heart problems. Cardiac monitors continuously track heart activity; patients undergoing testing may have to wear a portable device around their neck, which hooks up to wires from several electrodes stuck to the chest, perhaps for days at a time. Doctors can implant Medtronic’s new monitor using a syringe-like system that inserts the device into a small incision above the heart that is just eight millimeters deep. The monitor can then wirelessly transmit heartbeat data to a bedside monitor or potentially even to a smart phone, says Mark Phelps, an engineer leading Medtronic’s miniaturization efforts.

Radiation Exposure Won't Stop a Manned Mission to Mars

The risk of radiation exposure is not a show-stopper for a long-term manned mission to Mars, new results from NASA's Curiosity rover suggest.
A mission consisting of a 180-day cruise to Mars, a 500-day stay on the Red Planet and a 180-day return flight to Earth would expose astronauts to a cumulative radiation dose of about 1.01 sieverts, measurements by Curiosity's Radiation Assessment Detector (RAD) instrument indicate.
To put that in perspective: The European Space Agency generally limits its astronauts to a total career radiation dose of 1 sievert, which is associated with a 5% increase in lifetime fatal cancer risk.

"It's certainly a manageable number," said RAD principal investigator Don Hassler of the Southwest Research Institute in Boulder, Colo., lead author of a study that reports the results Monday in the journal Science.
A 1-sievert dose from radiation on Mars would violate NASA's current standards, which cap astronauts' excess-cancer risk at 3 percent. But those guidelines were drawn up with missions to low-Earth orbit in mind, and adjustments to accommodate trips farther afield may be in the offing, Hassler said.
"NASA is working with the National Academies' Institute of Medicine to evaluate what appropriate limits would be for a deep-space mission, such as a mission to Mars," Hassler told SPACE.com. "So that's an exciting activity."
The new results represent the most complete picture yet of the radiation environment en route to Mars and on the Red Planet's surface. They incorporate data that RAD gathered during Curiosity's eight-month cruise through space and the rover's first 300 days on Mars, where it touched down in August 2012.
The RAD measurements cover two different types of energetic-particle radiation — galactic cosmic rays (GCRs), which are accelerated to incredible speeds by far-off supernova explosions, and solar energetic particles (SEPs), which are blasted into space by storms on our own sun.

RAD's data show that astronauts exploring the Martian surface would accumulate about 0.64 millisieverts of radiation per day. The dose rate is nearly three times greater during the journey to Mars, at 1.84 millisieverts per day.
But Mars' radiation environment is dynamic, so Curiosity's measurements thus far should not be viewed as the final word, Hassler stressed. For example, RAD's data have been gathered near the peak of the sun's 11-year activity cycle, a time when the GCR flux is relatively low (because solar plasma tends to scatter galactic cosmic rays).
Curiosity's radiation measurements should help NASA plan out a manned mission to Mars, which the space agency hopes to pull off by the mid-2030s, Hassler said. And they should also inform the search for signs of past or present life on the Red Planet — another top NASA priority.
For example, the new RAD results suggest that microbial life is unlikely to exist right at the Martian surface, Hassler said. But future missions may not have to drill too deeply underground to find pockets of Mars life, if it ever existed.
"These measurements do tell us that we think it could be viable to find signs of possible extant or past life as shallow as 1 meter deep," Hassler said.
The new study is one of six papers published in Science Monday that report new results from Curiosity. Most of the other studies present evidence that the rover has found an ancient freshwater lake that could have supported microbial life for tens of thousands, and perhaps millions, of years.

Curiosity Rover Finds Ancient Life-Supporting Lakebed on Mars

The site where NASA’s Mars rover Curiosity landed last year contains at least one lake that would have been perfectly suited for colonies of simple, rock-eating microbes found in caves and hydrothermal vents on Earth.
Analysis of mudstones in an area known as Yellowknife Bay, located inside the rover’s Gale Crater landing site, show that fresh water pooled on the surface for tens of thousands — or even hundreds of thousands — of years.

“The results show that the lake was definitely a habitable environment,” Curiosity lead scientist John Grotzinger, with the California Institute of Technology, told Discovery News.
The really big surprise, however, was that clays drilled out from inside two mudstones and analyzed by the rover are much younger than scientists expected, a finding that extends the window of time for when Mars may have been suitable for life.

These numbers now overlap with the oldest rocks on Earth that contain evidence of a former biosphere on Earth,” Grotzinger said.
The rover explored Yellowknife Bay before heading toward a three-mile high mountain of layered sediments rising from the floor of Gale Crater known at Mount Sharp

Curiosity landed in August 2012 to assess if Gale Crater had the right ingredients and environments to support ancient microbial life. Within six months, scientists had the answer to that question: Yes.
Now, in addition to characterizing specific potential habitats, scientists are coming up with a search strategy to determine which sites hold the most promise for finding organic carbon, a far more difficult and complex challenge and the focus of future studies at Mount Sharp.
“Habitability only requires that the chemicals and minerals in the rock preserve evidence of an ancient environment. To search for organic carbon you’re actually looking for particular material ... that is not really compatible with the present environment of Mars. To find something you need a guidebook, you need some rules,” Grotzinger said.
One of those rules involves how much radiation a rock has been exposed to. Mars today has only has a thin atmosphere and no protective magnetic field, so scientists have been thinking they will need to dig deep to find carbon-laced samples, or they will have to probe craters relatively recently excavated by an impact.
Analysis of the Yellowknife Bay rocks points to another path. Dating the ages of the rocks’ surfaces show they are as young as about 70 million years, the result of being sand-blasted by Martian winds.

“In the future, if we find a rock that looks like a place where organics were accumulating and if it looks like the chemistry would have been favorable for preservation ... we can now very deliberately manage the risk that the rock would have been cooking away in the presence of radiation for hundreds of millions of years by looking for these scarps, these miniature cliffs, and then drilling the rock and date it to see how long it’s been laying around,” Grotzinger said.
In related research, scientists found that the amount of radiation measured by Curiosity during its first year on the Martian surface is about 40% of what the rover experienced during its nine-month cruise.
Most of the reduction, as expected, is due to the planet’s body serving as a buffer, but scientists also found that solar activity is a key factor, said Cary Zeitlin at Southwest Research Institute.
Six papers on Curiosity’s new findings are published in this week’s journal Science and unveiled at the American Geophysical Union conference in San Francisco.