SUNSET: 
The Kavli Foundation Q&A: Microbes and the Search for Extraterrestrial Life
Courtesy of The Kavli Foundation, Sky & Telescope is featuring an in-depth Q&A with two renowned astrobiologists on the search for extraterrestrial life.
The Kavli Foundation Q&A: Dark Matter at Long Last? Three New Experiments Ramp Up
Three astrophysicists discuss preparations for three recently funded dark matter experiments, and the likelihood that one of them will strike gold.
Zodiacal Light - Captivated by Comet Dust
October's a perfect time to see the zodiacal light, a tapering tower of comet dust standing high in the eastern sky before dawn. Here's how to find it.
Earthshine, the Moon's Darker Side
Explore the Moon's dark side with the aid of earthshine.
Is space flat or curved?
Locally, spacetime is curved by the presence of massive objects. The total mass and energy density of the universe also has an effect on the overall curvature of space.
What came before the Big Bang?
There was no “before the Big Bang"—the Big Bang created both time and space as we know it.
What is dark matter?
Dark matter is a mysterious type of matter that doesn't interact with any form of electromagnetic radiation, i.e., light. Although we’ve never detected dark matter directly, a large amount of evidence points to its existence.
How fast is the universe expanding?
Just how quickly is the universe expanding? Cosmologists attempt to answer this question in terms of the Hubble Constant, but the exact value of this constant is still a topic of debate.
Is the universe infinite?
Is the universe infinite, or just really, really big? How can we know? To answer these questions, we examine the possible shapes of the universe.
Power and Aperture in Binoculars
They come in a wide range of apertures. But for astronomy, large aperture is only part of the story. High magnification is just as important when binoculars are used on a night sky that's not absolutely dark.
How Far is the Closest Star?
Barring the Sun, the closest star to Earth is a triple system called Alpha Centauri, which is over four light years away.
How is Time Changed Inside a Black Hole?
Because black holes severely warp the fabric of spacetime, they have a curious effect on the passage of time as seen by an outside observer.
Sizes of Black Holes: How Big is a Black Hole?
Black holes are singularities: points of infinitely small volume with infinite density. However, the amount of a mass concentrated in a black hole varies, and the mass determines how wide the black hole's sphere of influence is.
How do black holes form?
Different types of black holes form through different processes.
Are Black Holes Real? If so, Who Discovered Them?
The concept of a black hole was first contrived in by John Michell 1783. For a long time, many notable scientists, including Albert Einstein, believed black holes were merely theoretical. However, in the last century, astronomers have gathered a good deal of observational evidence for the existence of black holes.
What is a black hole?
A black hole is a region of space where the force of gravity is so strong that the escape velocity exceeds the speed of light.
What's the Origin of the Universe? What happened during the Big Bang?
The Big Bang marked the beginning of the universe's expansion from a singularity — a single point that was infinitely small, infinitely hot, and infinitely dense. Cosmologists have designated several distinct eras for the universe's evolution from the first moments after the Big Bang to a billion years later.
What is dark energy?
Cosmologists have invoked the concept of dark energy to explain the accelerated expansion of the universe, but the nature of dark energy remains one of the most pressing questions facing modern cosmology.
Is there a center of the universe?
The universe began as a singularity that started expanding in the Big Bang. But the Big Bang was no regular explosion. Rather, space itself expanded, so there is no center of the entire universe. The observable universe, on the other hand, is a different story.
How Many Galaxies Are There in the Universe?
Astronomers determine the number of galaxies in the universe by counting up the number visible in a tiny portion of the sky, and then accounting for all the regions of the observable universe. A 2013 study estimates that there are 225 billion galaxies in the observable universe.
