Blog Archives

Curious Stains on Mars’ Summer Slopes Continue to be Seen

Recurring slope lineae (RSL) stain mountain slopes in Hale Crater. (NASA/JPL/University of Arizona)

Recurring slope lineae (RSL) stain mountain slopes in Hale Crater. (NASA/JPL/University of Arizona)

As the midsummer Sun beats down on the southern mountains of Mars, bringing daytime temperatures soaring up to a balmy 25ºC (77ºF), some of their slopes become darkened with long, rusty stains that may be the result of water seeping out from just below the surface.

The image above, captured by the HiRISE camera aboard NASA’s Mars Reconnaissance Orbiter on Feb. 20, shows mountain peaks within the 150-km (93-mile) -wide Hale Crater. Made from data acquired in visible and near infrared wavelengths the long stains are very evident, running down steep slopes below the rocky cliffs… but the process that’s responsible for them has yet to be confirmed.

Read the rest of my article on Universe Today.

Cassini Captures Narrow-Angle, Wide-Spectrum Views of Rhea

Composite image of Saturn's moon Rhea from Feb. 9, 2015. Credit: NASA/JPL-Caltech/SSI.

Composite image of Saturn’s moon Rhea from Feb. 9, 2015. Credit: NASA/JPL-Caltech/SSI.

After spending a couple of years in an orbit riding high over the northern pole of Saturn Cassini has swung back down alongside the planet’s ringplane, in perfect alignment to once again capture views of the icy moons that reside there. The image above is a composite made from several narrow-angle camera images acquired by Cassini on Feb. 9, 2015, showing an extended color view of Rhea as the spacecraft was heading to perform a targeted flyby of the larger haze-covered moon Titan.

Saturn’s second-largest moon, the heavily-cratered Rhea wouldn’t appear this golden to our eyes; its natural colors are much more monochromatic (i.e., grey.) But Cassini can “see” in light stretching from ultraviolet to infrared, and that added range lets us see Rhea in a new light.

Read the rest of this article on Discovery News here.

Ground-Based Radar Reveals the Surface of Venus

Radar map of Venus' surface made from signals sent from Puerto Rico and received in West Virginia (NRAO)

Radar map of Venus’ surface made from signals sent from Puerto Rico and received in West Virginia (Credits: B. Campbell, Smithsonian, et al., NRAO/AUI/NSF, Arecibo)

These days if you look toward the west after sunset you’ll see a bright star that’s the first to appear in the sky – except it’s not a star at all but our neighboring planet, Venus. Covered in a dense layer of thick clouds, Venus not only reflects a lot of sunlight but also keeps its surface well concealed from visible-light observations. But with the capabilities of powerful ground-based radar observatories, scientists have been able to make global maps of Venus from right here on Earth… no rockets necessary!

Read the rest of my article on Discovery News here.

Ganymede’s Aurorae Hint at an Ocean Ten Times Deeper than Earth’s

Illustration of Ganymede's auroral ovals, the stability of which hint at a global underground ocean. Credit: NASA, ESA, and G. Bacon (STScI).

Illustration of Ganymede’s auroral ovals, the stability of which hint at a global underground ocean. Credit: NASA, ESA, and G. Bacon (STScI).

It’s long been suspected that Jupiter’s giant moon Ganymede may harbor a subsurface ocean of liquid water beneath its icy yet hard-as-rock crust, and now some ingenious observations with the Hubble Space Telescope are making an even more convincing case for it!

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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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Remembering Huygens’ Titan Landing, Ten Years Later

First color image from the surface of Titan, Jan. 14, 2005 (ESA/NASA/JPL/University of Arizona)

This incredible image was captured ten years ago today, on January 14, 2005. It shows the murky surface of Saturn’s moon Titan as seen by the European Space Agency’s Huygens probe after it made its historic descent through the moon’s thick haze and clouds and landed in a frozen plain of crusty methane mud and icy pebbles. During the descent and after landing Huygens returned data for several hours before communication was lost. The groundbreaking images and information it sent back has proved invaluable to scientists studying this unique and mysterious moon, which is at the same time extremely alien and surprisingly Earth-like.

“It was eerie…we saw bright hills above a dark plain, a weird combination of light and dark. It was like seeing a landscape out of Dante.”

– Jonathan Lunine, Cassini-Huygens mission scientist

Learn more about the Huygens landing here and check out an incredible video below zooming in a billion times from Saturn orbit to Titan’s surface:

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