火星、地球和太阳将会三点一线

Now's a great time to break out that backyard telescope. Because Saturday, March 3, is the Mars Opposition. It's one of the times that the Earth and Mars pass the closest to one another. The name - the Mars opposition - means that Mars and the Sun are on, well, opposite sides of us. And it happens only once every two years and two months.

But if you don't have such equipment handy, you might want to head over to the online Slooh Space Camera.

It's usually a members-only site that allows users to look at web images broadcast from telescopes around the world and to click to snap photos. The pictures get integrated into Google Earth/Sky. The site also offers free weekly space shows.

But Saturday there'll be a free live streaming of the Mars Opposition, hosted by astronomy experts. It'll include views of the planet from a variety of observatories including those in Arizona and the Canary Islands. You'll be able to pick out surface features such as canyons, volcanoes and polar caps.

The online broadcast will begin on Saturday at 11 pm Eastern time. Head over to the online Slooh Space Camera.

--Cynthia Graber