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Our Five-Trillion-Mile Close Call: the Star(s) That Skimmed the Solar System

Artist's rendering of two stars that made a close pass by the Sun 70,000 years ago. (Michael Osadciw/University of Rochester)

Artist’s rendering of two stars, a red dwarf and a brown dwarf, that made a close pass by the Sun 70,000 years ago. (Michael Osadciw/University of Rochester)

It’s like something out of a Hollywood film or a science fiction novel: a dark star sneaks up on Earth from just outside the Solar System, discovered too late to do anything about it (and really, what could we do?) and plows through the cloud of comets that surrounds the Sun like a haze of icy gnats, sending them flying everywhere… including on collision courses with Earth. Mass hysteria ensues.

Except that this isn’t just a story concept – scientists think this is actually something that happened 70,000 years ago! Minus the mass hysteria, of course… our ancestors were just beginning to settle down in the fertile lands of the Middle East after wandering out of Africa and would have had no idea what was happening at the edges of the Solar System (besides maybe a bright star occasionally flaring up in the night sky.)

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Latest Images of Ceres Show Its Bright Spot Is Actually Twins!

Image of Ceres captured by Dawn on Feb. 19, 2015.

Image of Ceres captured by Dawn on Feb. 19, 2015.

Here’s your weekly Ceres update! The dwarf planet’s features are coming into better and better focus for the approaching Dawn spacecraft, which will be captured by Ceres’ gravity on March 6. The image above is yet another “best-ever” of Ceres (as will be each one we see now), captured on Feb. 19, 2015, from a distance of about 29,000 miles (46,000 km).

This was one of a trio of images from Dawn released today. The others can be seen below, including one that shows the intriguing bright spot that has been observed for over a decade.

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Rosetta Gets Up Close and Personal With Comet 67P

The surface of 67P/C-G imaged by Rosetta on Feb. 14, 2015 from about 8.9 km (Credits: ESA/Rosetta/NavCam – CC BY-SA IGO 3.0)

The surface of 67P/C-G imaged by Rosetta on Feb. 14, 2015 from about 8.9 km (Credits: ESA/Rosetta/NavCam – CC BY-SA IGO 3.0)

On Saturday, Feb. 14, 2015, the Rosetta spacecraft performed a bit of a barnstorming act, swooping low over the surface of comet 67P/C-G in the first dedicated close pass of its mission. It came within a scant 6 km (3.7 miles) of the comet’s surface at 12:41 GMT. The image above is a mosaic of four individual NavCam images acquired just shortly afterwards, when Rosetta was about 8.9 km from the comet.

Higher-resolution OSIRIS images should be downlinked from the spacecraft within the next few days.

The view above looks across much of the Imhotep region along the flat bottom of comet 67P’s larger lobe. (See a map of 67P’s named regions here.) At the top is the flat “plain” where the Cheops boulder cluster can be seen – the largest of which, Cheops itself, is 45 meters (148 feet) across.

After the close pass Rosetta headed out to a distance of about 253 km (157 miles) before beginning preparations to approach closer again. Over the course of Rosetta’s mission this year flybys will be the “new normal,” but none will be as close as the Feb. 14 pass.

Watch a video from ESA about the close pass below, and find more images from the flyby in my article on Universe Today here.

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Hello, Ceres! Dwarf Planet’s Features Come Into Focus

Image of Ceres captured by NASA's Dawn spacecraft during approach on Feb. 12, 2015. Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.

Image of Ceres captured by NASA’s Dawn spacecraft during approach on Feb. 12, 2015. Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.

Won’t you look at that! Here’s a view of Ceres captured by NASA’s Dawn spacecraft on Feb. 12, 2015, from a distance of about 52,000 miles (83,000 km). No longer just a grey sphere with some vague bright spots, actual features can now be resolved – craters, mountains, and scarps that quite literally no one has ever seen before! Fantastic!

Two images were captured by Dawn’s framing camera as Ceres rotated within view over the course of its 9-hour day. See both below:

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Despeckled Radar Images Give a Clearer View of Titan’s Shores

Before despeckling (top) and after (bottom) images of portions of the shoreline around Ligeia Mare, Titan's second-largest hydrocarbon sea.  Credits: NASA/JPL-Caltech/ASI

Before despeckling (top) and after (bottom) images of portions of the shoreline around Ligeia Mare, Titan’s second-largest hydrocarbon sea. Credits: NASA/JPL-Caltech/ASI

At 1,600 miles (2,576 km) across Titan is by far Saturn’s largest moon – in fact it’s the second-largest satellite in the solar system. It’s also the only world besides Earth where liquids have been found in large amounts on the surface, in the form of lakes and streams of frigid methane and ethane. This makes Titan an intriguing subject of study for planetary scientists, but unfortunately it’s not all that easy to get a good look at its surface because of its thick orange clouds and dense atmosphere.

Now, researchers have developed a “despeckling” method to smooth out Cassini’s typically grainy radar maps, giving scientists a whole new way to look at Titan’s alien — yet surprisingly Earth-like — surface.

Read the rest of my article on Discovery News here. 

Voyager’s Valentine Turns 25 Today

If you’re in love with space exploration then you’ll fall for this: it’s the picture of Earth taken from the Voyager 1 spacecraft after it passed the orbit of Pluto in 1990. That image of our planet from almost 4 billion miles away inspired Carl Sagan to write his famous “Pale Blue Dot” passage, and reminds us that we are all just floating on “a mote of dust suspended in a sunbeam.”

This is from a post I originally published in 2010. I’ll keep trotting it out until it’s not cool anymore. (Which I don’t think will ever happen.)

Venus, Earth, Jupiter, Saturn, Uranus and Neptune as seen by Voyager 1 in 1990 (Credit: NASA)

On February 14, 1990, after nearly 13 years of traveling the solar system, the Voyager 1 spacecraft passed the orbit of Pluto and turned its camera around to take a series of photos of the planets. The image above shows those photos, isolated from the original series and are left to right, top to bottom: Venus, Earth, Jupiter, Saturn, Uranus, and Neptune.

From that distance, over 4 billion miles from the Sun, the planets each appear as little more than a bright dot against the vastness of interplanetary space.

“That’s here. That’s home. That’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. … There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world.”

– Carl Sagan

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