variable

"To be is to be the value of a variable." -Willard Van Orman Quine It's the end of the week once again, and the very end of our Year In Space 2014 Wall Calendar giveaway! So for this week's Ask Ethan column, after dipping into our question/suggestion box, I'm very pleased to let Vera from Italy know that her question was the winning one, as she asked: I saw the video you posted about  the variable star RS Puppis, by the Hubble Space Telescope, and I really would like a post about what exactly are variable stars. Thank you very much Ethan!! :-) So -- no burying the lede here -- there was a…

"We find them smaller and fainter, in constantly increasing numbers, and we know that we are reaching into space, farther and farther, until, with the faintest nebulae that can be detected with the greatest telescopes, we arrive at the frontier of the known universe." -Edwin Powell Hubble With 110 deep-sky objects scattered throughout the heavens, the Messier Catalogue provides skywatchers across the globe with a number of spectacular targets, from nearby nebulae and clusters to spectacular, distant galaxies. Each Monday, we spotlight a new one right here. Image credit: Rolando Ligustri,…

Warning: Crazy talk ahead. Some of you may remember that I wrote about inflation and why its alternatives fail awhile back. Apparently, Louise Riofrio didn't get the memo. When there's misinformation about cosmology out there, it's up to me to set the record straight. (And I am not alone.) Let me first remind you about one of the alternatives to inflation I debunked last month: Add defects and vary the Speed of Light. This one’s out. Why? Because we would see defects in the Cosmic Microwave Background, and we don’t. The constancy of the speed of light is highly supported by experiments, but…