OUR UNIVERSE

A faraway star's mysterous dimming was most likely caused by comets, a new study suggests — though it doesn't rule out the much-ballyhooed possibility of an "alien megastructure" in the system. Observations by NASA's planet-hunting Kepler space telescope revealed that the star KIC 8462852, which lies about 1,500 light-years from Earth, dipped in brightness dramatically in 2011 and 2013, dimming by up to 22 percent. Such deep brightness dips puzzle astronomers, who have advanced a number of possible explanations, from a gigantic asteroid collision to a cloud of broken-apart comets to an enormous energy-collecting structure built by an advanced alien civilization. (The alien-megastructure hypothesis is unlikely but nonetheless warrants consideration, many astronomers have said.) Artist's illustration showing a star behind a shattered comet. Credit: NASA/JPL-Caltech ...

A photon leaps off the sun and, about 500 seconds later, bounces off our Earth. Light has been dancing and rebounding from faraway and nearby celestial objects for more than 13 billion years. It's time you caught some of it for your very own. That's what telescopes do; they gather light. But which telescope you choose to collect that radiance will vary according to your needs and budget. Our editors have selected a few of the best options in four categories. Click on each to read a review of the telescopes in these groups: Best Hobbyist Telescopes for Serious Sky watchers Best Small, Portable Telescopes for Travelers and City-Dwellers Easiest Telescopes for Beginners (Easy to Use) Best Inexpensive Telescopes (A Great Gift Idea) Space.com Editors have selected 12 Great Telescopes in 4 Categories. Are you a traveler? Student of the sky? On a budget? Live in a small home? Do you like digital tech? Or prefer an analog approach? ...

And 'how much longer until a new discovery shouts it out?' asks the Science @ NASA video series. In July 2014, NASA announced the discovery of Kepler 452b, a planet slightly larger than …Read More » Earth that resides in the habitable zone of its solar system. It is 6 billion+ years old, (older than Earth) allowing for plenty of time for life to develop.

So how thick is what we call sky? Well, you'd think, looking up, that there's so much blue up there it's got to go on for hundreds and hundreds of miles. But it doesn't. Looking at this photo, you can see that the ring of atmosphere around the earth is cellophane thin...a wisp of gas. It's a little thinner at the poles and thicker near the equator, but the "sky" is about 250 miles wide (or up), the distance, roughly, between New York City and Washington, D.C. Which means — if Amtrak could run a "Sky Chief" straight up and handle the spin — you could chug to the very edge of space in three and a half hours. But that's not the cool part. In the 1940's, the great illustrator Eric Sloane did a cross-section of the atmosphere that surrounds our planet. He observed that we live in a sea of air, and we, like lobsters, are at the bottom: Eric Sloane/Dover Publications Then he took a closer look at that bottom piece, ...

Astrophotographer Brian Hancock sent in a photo of the Milky Way over a moai near Hanga Roa on Easter Island in the south Pacific Ocean, a province of   Chile. He writes in an email message to  Space.com : “Just wanted to share a ... [photo] from a recent trip to Chile this past October. I honestly was totally lost when I first looked up — familiar constellations like Sagittarius and Scorpius were so ‘out of place’ that I didn't recognize them at first. [This] photo is from a night of observing at a moai near Hanga Roa. It is right by the shore and clouds rolled in as the Milky Way hovered above.”

Before twilight and shortly after the moon set in Yellowstone National Park, astrophotographer  A. Garrett Evans  found the perfect moment to capture this stunning image. Made up of dust, gas and roughly 400 billion stars, the Milky Way is a barred spiral galaxy stretching between 100,000 to 120,000 light-years in diameter. It is visible as a dazzling band of light in the night sky. The steam from the spring can be seen center right in the frame. The lines in the foreground created by the silica and the colors created by the microbial mats that grow around the edge of the spring. "All the sights in the park are amazing some maybe even more so at night!" Evans added. This photo is a single shot taken with a Canon 6D, using a Nikon 14024 mm lens with a Novoflex adapter. Camera settings were ISO 6400, f/2.8, 30 seconds.

The Alpha Centauri system is the closest star system to our sun. On our sky’s dome, we see this multiple system as a single star – the third-brightest star visible from Earth.                                                     Alpha centauri three stars compared to our parent star the SUN The Alpha Centauri system probably consists of three stars. Alpha Centauri is part of a double, or triple, star system. The two main components are Alpha Centauri A and Alpha Centauri B. The third star, a red dwarf called Proxima Centauri, is thought to be about 4.22 light-years distant and is actually our sun’s closest neighbor among the stars. Is it part of the Alpha Centauri system? The actual status of Proxima as a system member is unclear. It might simply be passing nearby but not part of the system, or it might be gravitationally bound. Still, we say – and o...

NASA astronaut Scott Kelly took this photo of sunrise — looking like an abstract painting — over Earth's horizon from the International Space Station on Oct. 21, 2015.

In 2005, NASA’s Cassini spacecraft discovered that geysers blast water ice, organic molecules and other material into space from the south polar region of the Saturn moon Enceladus. Credit: NASA/JPL/SSI NASA's Cassini spacecraft has made its deepest dive yet through the plume emanating from the south pole of Saturn's icy moon Enceladus. Cassini flew low through the plume today (Oct. 28) at about 1 p.m. EDT (1700 GMT), zooming within a mere 30 miles (50 kilometers) of Enceladus' frigid surface, if all went according to plan. During the encounter, the spacecraft snapped photos and gathered samples that should help researchers learn more about the moon's life-hosting potential. (An ocean of liquid water sloshes beneath Enceladus' icy shell, and the plume material comes from this subsurface sea.) Enceladus has an extensive water ocean under its icy crust, feeding water jets that emerge from near the so...

It's easy to get lost in this jaw-dropping snapshot of the Eagle Nebula, which offers a high-resolution view of an incredible space landscape. The Eagle Nebula is a massive collection of gas and dust, which serves as fertile soil for the birth of new stars. The blue, lagoonlike region at the center of the image contains the iconic, fingerlike structures known as the Pillars of Creation. The blue, green and red indicate the presence of different gasses. The image was created by a collaboration of four astrophotographers, and is composed of 177 individual frames, with a total integration time of 32 hours. The group members are Terry Hancock of Michigan (whose sky images have been featured on Space.com many times before), Gordon Wright from Scotland, Colin Cooper, Spain; and Kim Quick, Florida. The full-size image is almost too much to take in all at once, so viewers are encouraged to zoom in and get lost in the details of this incredible snapshot. Pillars o...

Artist's illustration of NASA's Cassini spacecraft flying by Saturn's icy moon Enceladus. Cassini will make its deepest-ever dive through Enceladus' south polar plume on Wednesday (Oct. 28). Credit: NASA/JPL-Caltech Scientists are about to get their best look ever at the ocean that sloshes beneath the surface of Saturn's icy moon Enceladus. On Wednesday (Oct. 28), NASA's Cassini spacecraft will zoom just 30 miles (50 kilometers) above Enceladus, flying through and sampling the plume of material that erupts from the satellite's south polar region. This plume is thought to originate from Enceladus' underground liquid-water ocean, so Cassini's onboard sample analysis should shed light on the moon's potential to host life, mission team members said.   Mission Video  "On Wednesday, we will plunge deeper into the magnificent plume coming from the south pole than we ever have before, and we will collect the best samples ever...