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The image also shows evidence that water once flowed and lakes once stood on the Martian surface. White lines are channels cut by water and lighter-coloured regions indicate deposits of sulphate components. Rock formations display evidence of flow textures, indicating that they were once deposited by liquid water, water ice or mud.
- Mars: how low can you go? (spacefellowship.com)
- See the depths of Mars … in 3-D! (cosmiclog.msnbc.msn.com)
- The freezing oceans of ancient Mars were home to great icebergs [Mad Astronomy] (io9.com)
Stephen Hawking: “Why Isnt the Milky Way Crawling With Mechanical or Biological Life?” Todays Most Popular
Metaphor for an astronomical quest, a mechanical firefly is just a glimmer next to a 5-foot-wide (1.5-meter-wide) searchlight. Astronomers hoping to capture the light of an Earth-size planet around a star billions of times brighter compare the feat to picking a firefly from a searchlight’s glare 3,000 miles (4,800 kilometers) away, on a foggy night.
Photograph by Mark Thiessen
Written by Tim Appenzeller
Republished from the pages of National Geographic magazine
It’s past midnight in the dim telescope control room, but Dominique Naef’s day has suddenly brightened. He twitches his computer cursor over a wavy line. “I like it,” the Swiss astronomer says, beaming. “I like it a lot. Wow.”
Fifty light-years away in the night sky, a star like our sun is doing a stately dance, stepping toward Earth and away again. From the La Silla Observatory in the mountains of Chile, Naef and his colleagues have stolen glimpses of the dance for months. But for much of that time their view was blocked by clouds, a foot of snow, and, this August night—midwinter in Chile—humidity so high that the telescope dome had to be shut to keep out frost. Earlier in the evening, between cups of espresso and cigarette breaks, Naef gloomily eyed a display of weather data. He feared another lost night.
Then the humidity dropped, and the telescope operator gave the go-ahead. Naef and Christoph Mordasini, a graduate student from Bern, huddled at their screens. They captured one more reading of the star’s motion before, minutes later, the humidity shot up again and the operator called a halt for the night.
It’s just another glimpse, but it’s enough to turn a suspicion into a near certainty. The excited jiggle of Naef’s cursor shows that the reading has fallen just where it should if an unseen planet is tugging the star to and fro. The next day the team leader, veteran planet hunter Michel Mayor of the University of Geneva, decides that it’s time to announce the discovery. If it stands up to the scrutiny of other scientists, this planet, around a star called Mu Arae, will be a milestone in the quest for another Earth.
The most massive planet in our solar system, with four planet-size moons and many smaller satellites, Jupiter forms a kind of miniature solar system. Jupiter resembles a star in composition. In fact, if it had been about eighty times more massive, it would have become a star rather than a planet.
On January 7, 1610, using his primitive telescope, astronomer Galileo Galilei saw four small “stars” near Jupiter. He had discovered Jupiter’s four largest moons, now called Io, Europa, Ganymede, and Callisto. Collectively, these four moons are known today as the Galilean satellites.