They are one of nature's most spectacular sites: The aurora borealis, or northern lights as they are known, have captivated onlookers for thousands of years.
This past weekend saw a particularly stunning display following a phenomenon known as a coronal mass ejection, where the sun spews a burst of particles into space that reach Earth one to three days later.
Bursts toward earth can cause electromagnetic storms when they react with the Earth's magnetic field, resulting in an explosion of color in the sky.
By CNN Staff
Skywatchers set their alarm clocks for the early morning hours Thursday when the annual Quadrantid meteor shower peaked.
Meteor watchers could have expected to see 60 to 200 meteors an hour streak across the sky, according to NASA, but if you found that visibility was low, blame it on the moon: NASA warned that moonlight could make seeing the Quadrantids harder.
Bill Cooke, the head of NASA's Meteoroid Environment Office, said by e-mail that the shooting stars would be visible after about 11 p.m. in each time zone in the United States, with the best viewing time from 3 a.m. until dawn. Now that the shower has peaked, skywatchers with clear, dark skies may be able to see a few more meteors around 11 p.m. EST.
By Claire Colbert, CNN
Our readers were certainly intrigued by initial measurements from the Mars rover Curiosity recently, which indicated that radiation levels on Mars are not lethal to humans. More research needs to be done to determine exactly how much radiation exposure a visit to Mars would entail, however.
Curiosity has been on Mars since August 6. For several weeks it had been parked at a place called Rocknest, but on November 16 the rover started driving again, NASA said. Currently it's on its way to a location called Point Lake.
As we continue to chart its activities here at CNN Light Years, it seems that every new discovery that the rover makes rekindles the debate about the importance, or lack thereof, of NASA.
Editor's note: This post is part of the Overheard on CNN.com series, a regular feature that examines interesting comments and thought-provoking conversations posted by the community.
Last week, NASA scientists announced that the Mars rover Curiosity had found something unexpected: small bright objects. These one-millimeter flecks didn't appear to originate from the rover, but rather from Mars itself. They could be part of the soil forming process, or they could be minerals cut in particular ways that make them look shiny in sunlight.
More than 550 people commented on this story. Most people had fun guessing what the shiny objects might be.
Comments on CNN Light Years consistently flood in about how the money spent on the space program isn't worth it. We often see the word "waste" in connection to the tax dollars that go toward exploring the rest of the universe beyond our planet.
So, we ran a story this weekend about what innovations space exploration has delivered. Examples included digital image processing used in medical scanning, GPS and state-of-the-art tires.
As expected, readers expressed a variety of opinions upon reading this story. Some were sympathetic with the viewpoint of the middle-class mother interviewed for the article, who cringes when she thinks about tax dollars going to NASA, and wishes she had more funding for her daughter's college tuition.
The Orionid meteor shower put on a cosmic light show for the Northern Hemisphere over the weekend. The Orionids peaked early Sunday morning as more than 25 meteors an hour streaked the night sky.
The astronomical event caught the attention of many photographers over the weekend. iReporters from across the world stayed up late or woke up early for the chance to catch a glimpse of the meteor shower.
Renata Arpasova set her alarm a few hours early, waking up at 1 a.m. to see the Orionids from Wiltshire, England. She found a clear patch of sky and was thrilled to see a few big, bright meteors pass overhead.
By Jareen Imam, CNN
Silver fireballs will streak over the Northern Hemisphere on Saturday and Sunday. The much-anticipated Orionid meteor shower is scheduled to peak over the weekend, greeting October skies and stargazers with a brilliant show.
The Orionid meteor shower will peak about 12:00 a.m. PST Sunday, although there may be meteor sightings before and after, says Karen Randall, director of special projects at SETI Institute. The “shooting stars” will be even more visually prominent because the new moon will be setting about midnight Saturday, allowing for a view unaffected by bright moonlight, according to NASA.
The best time to view is Sunday morning, NASA says: Wake up an hour or two before the sun comes up; the constellation Orion will be high in the sky. You don't even need a telescope; you can just lie down and look up.
The space shuttle Endeavour is making its way through Inglewood and Los Angeles to the California Science Center.
Here's how Los Angeles prepared for the road trip - moving trees, power poles and streetlights to cope with the very wide load.
Editor's note: We're listening to you. Every day, we spot thought-provoking comments from readers. Here's a look at what readers are saying.
Earth's largest satellite helps create our tides and makes moonlit rides possible. The white ball adorned in shadows and craters has long confounded and beckoned us, and Apollo 11 Commander Neil Armstrong became the first human to set foot on the moon's dusty surface. Buzz Aldrin and Michael Collins were with him on a mission that inspired many more small steps.
News that Armstrong had died got our readers reminiscing about the many little impacts from mankind's giant leap into the future.
"I was born in the 1970s and back then you just didn't throw out a name for your child. There was an importance to naming a child. My parents thought someone to walk on the moon was significant. They wanted to capture the hope."
He says he felt great sadness when he learned that Armstrong had died.
"I was talking to my dad, and he said your godfather passed away. My first reaction was, 'I haven't seen my father's side in ages,' and then my father said Neil Armstrong died," he wrote, and noted all the ways Armstrong had inspired him.
"Neil Armstrong, thank you for your accomplishments, your inspiration, for allowing us to do great things (reaching Mars for example), and most importantly, for giving us a name to remember. You can be sure that I will continue to speak about you for generations to come, and people will always know, why my name is Neil!"
Do you love to shoot the stars?
Join Light Years and CNN iReport on Facebook tomorrow at 2:30 p.m. ET for a chat with R. Jay GaBany, one of the world’s leading amateur astrophotographers.
Jay will answer your questions about celestial photography and share his tips for how to get the best brag-worthy snapshots of meteor showers, the Milky Way and the night sky using minimal equipment.
We look forward to seeing you there!