By Matt Smith, CNN
The meteor that exploded over the steppes of southwestern Russia sent a low-frequency rumble bouncing through the Earth, giving scientists new clues about the biggest cosmic intruder in a century.
The big boom over Chelyabinsk on February 15 also produced a wave of sound thousands of times lower than a piano's middle C - far below the range of human hearing, according to the international agency that watches for nuclear bomb tests. The Comprehensive Test Ban Treaty Organization said that sound wave showed up on sensors from Greenland to Antarctica, making it the largest ever detected by its network.
Scientists then used that wave to calculate the size of the small asteroid that plunged to Earth, said Margaret Campbell-Brown, an astronomer at Canada's University of Western Ontario.
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By Elizabeth Landau, CNN
Scientists have been able to pin down the most accurate estimate yet for how fast a supermassive black hole is spinning. The answer is "fast": near the speed of light.
The black hole in question is more than 2 million miles across, with a surface traveling near the speed of light. It is at the center of spiral galaxy NGC 1365 and is the equivalent of about 2 million solar masses. Don't worry, this black hole not an imminent danger to us, given that it's in a galaxy 60 million light years away.
OK, go ahead and get the "Where's my global warming?" jokes out of your system. With the U.S. Midwest trudging through its second blizzard in a week, we understand.
But while it may seem contradictory at first, scientists say bigger blizzards fit the pattern they expect to see from a changing climate.
The immediate meteorological cause of the back-to-back snowstorms is a colder-than-normal mass of air that's been hovering over the central United States, combined with an amped-up jet stream that's been dipping south from Canada. That makes conditions ripe for major snowstorms after a warmer-than-normal January for most of the Lower 48.
Follow @CNNLightYears on Twitter for more space and science updates.
By John Zarrella, CNN
If newly unveiled plans pan out, a man and a woman may represent humanity on one journey that has never been attempted before: a mission to Mars.
“It’s incredibly feasible. It’s not crazy talk," Taber MacCallum, CEO of Paragon Space Development Corp., told CNN.
MacCallum and millionaire Dennis Tito announced their plans Wednesday to send a couple of earthlings on a 501-day trip in a spacecraft that would fly by the red planet. The proposal was unveiled at the National Press Club in Washington.
By Sally Holland, CNN
The red roses of Valentine's Day have withered, and the yellow daffodils of spring have yet to bloom, so it's orchids that are having their time in the spotlight at the Smithsonian in Washington.
The orchids on display in an exhibit called Orchids of Latin America are strikingly vivid and manipulative.
"It is believed that at least a third of all orchids engage in some kind of deception," said Tom Mirenda, an orchid collections specialist at the Smithsonian Gardens.
Bill Nye "The Science Guy" weighs in on whether an asteroid will be a threat to Earth in the future. Check out the video above.
NASA hosted its first Google+ Hangout with astronauts on the International Space Station, allowing Earthly onlookers to ask questions by video.
Astronauts Kevin Ford, Chris Hadfield and Tom Marshburn answered questions, such as how they prepare for medical emergencies.
The answer is that they have on-board medical kits with everything from aspirin to an IV to a defibrillator. But if there were a real problem with one of the crew members, the Soyuz shuttle would act as an ambulance, they said.
The clip above shows the part of the video chat about dealing with medical problems. NASA also posted the full conversation, lasting more than an hour, on YouTube:
More from Light Years: Peter Gabriel hears his song from space
British singer Peter Gabriel got a brief serenade from a member of the International Space Station crew on Wednesday during a visit to Mission Control in Houston.
Canadian Chris Hadfield, Expedition 34's flight engineer, strummed a few chords of Gabriel's hit "In Your Eyes" during a nearly 12-minute chat with Gabriel and his family.
Hadfield told Gabriel that he recorded two songs in space. The first, co-written with his brother, is a "space Christmas carol" called "Jewel in the Night." The second, a space-to-Earth collaboration with Canadian band Barenaked Ladies, is called "I.S.S. (Is Somebody Singing)."
Click on the video above to hear Hadfield's performance.
By Nova Safo, CNN
Follow on Twitter: @nova_safo
The meteor that wreaked havoc in Russia last week, shattering windows around a 50-acre area and injuring 1,200 people, was not as big as the asteroids that Dr. Bong Wie of Iowa State University is worried about. He is researching how to stop one of the 400 asteroids scientists have discovered, which have some chance of crashing into Earth and potentially destroying a city.
Wie has gotten NASA’s attention with a plan that seems right out of the Hollywood blockbuster "Armageddon." He is working on a plan to bury a nuclear bomb into a potentially deadly asteroid and blow it up into tiny pieces.