Credit: Wing-Chi Poon

Cycles Of Time

We like marking time by the Sun. Its rising and setting marks a day, and its path along the ecliptic marks a year. The solar year seems to be our favorite marking of time. Its cycle follows the seasons, and so we have lots of annual celebrations, including our own special day. Of course there are lots of other ways we could mark our time. Read more

Watching A Black Hole From Your Back Yard

Black holes don’t emit light directly, but material around a black hole often does. As gas and dust falls toward a black hole, it’s often compressed and superheated, causing it to emit light. Usually the light we see is in the form of x-rays and gamma rays, since they can penetrate material surrounding a black hole. But recently we’ve observed visible light from material near a black hole, and with a decent telescope you could observe it from your back yard.  Read more

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What Are The Odds That Aliens Exist?

Recently the star KIC 8462852 (aka Tabby’s Star) has made news again because of its strange behavior. Possible explanations for its varying brightness (such as comets) don’t seem to fit the observational data, which has some speculating that the star’s behavior could be explained by the presence of an alien civilization. While many astronomers admit that is a possibility, they don’t think aliens are the likely cause. For one, mysterious behavior is not enough to conclude the cause is aliens. For another, the likelihood that an alien civilization actually exists is still a matter of some debate.  Read more

Credit: B. Saxton and F. Lockman (NRAO/AUI/NSF), and A. Mellinger

Leave It To Smith

There’s an interstellar cloud of gas heading for the Milky Way. It’s about 10,000 light years across, has a mass of a million Suns, and impact our galaxy in about 30 million years. Until now, it’s origin has been a mystery.  Read more

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How Large Can A Solar System Be?

Most of the star systems we’ve discovered have been small systems with planets close to a red dwarf star. This is largely due to the fact that large planets close to a star are easier to detect than smaller ones farther away. Our own solar system is fairly large by comparison, with the most distant planetary bodies being about 300 AU (or perhaps 700 AU) from our Sun. It raises an interesting question about just how large a planetary system could be. If a recent discovery pans out, the answer could be much larger than we expected.  Read more