
Giant Bubbles Tower over the Milky Way
Newly discovered lobes stretch tens of thousands of light-years above and below the Milky Way's disk. Where they come from remains a mystery

Giant Bubbles Tower over the Milky Way
Newly discovered lobes stretch tens of thousands of light-years above and below the Milky Way's disk. Where they come from remains a mystery

Spacecraft Sneaks Up on a "Sweaty" Comet
Over the coming month the European Space Agency’s (ESA) Rosetta mission will fire its main engines no less than eight times to tweak its interplanetary intercept course with Comet Churyumov-Gerasimenko; eventually sidling up to the 4 kilometer wide cometary nucleus at about 7.9 meters per second in early August.


Dwarf Galaxies Really Cooking with Gas
The smallest galaxies in the universe gave rise to an unexpectedly large proportion of stars. Karen Hopkin reports

"Extremely Large Telescope" Breaks Ground
The European Southern Observatory broke ground June 19th to build the world's largest telescope atop the Cerro Armazones mountain in Chile. Clara Moskowitz reports

If Spacetime Were a Superfluid, Would It Unify Physics—or Is the Theory All Wet?
Thinking of space and time as a liquid might help reconcile quantum mechanics and relativity

Jellyfish Galaxies Get Guts Ripped Out
Recently discovered galaxies shaped like jellyfish leave a long trail of hot gas and dust, victims of even hotter gas from their surrounding cluster of galaxies

Brazil and Other Big Players Lead in South American Science
Despite myriad problems in many countries, pockets of excellence thrive in Chile, Colombia, Brazil and Argentina

All Aboard the 100 Year Starship
In 2012, I asked LeVar Burton (who comandeered the Scientific American website as guest editor on Wednesday) if he would join me on a trip across time and space, to another star.

Is Seeing a Comet Like Halley’s a Once-in-a-Lifetime Event?

The Logic and Beauty of Cosmological Natural Selection
I have a prediction. There is a scientific hypothesis, formulated over 20 years ago, that we will one day look back on, when the evidence is in, and say “Of course that was right!

Lunar Rock Chemistry Argued to Reveal How the Moon Formed
Small differences in oxygen-isotope ratios have been used to support the big-smash theory

Space: A New Hope or an Old Dream?
The release of a long-awaited National Academy of Sciences report on the state and future of the US space program has triggered wide-reaching commentary on what it means to be space-faring.