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These Are Our Best Pictures of Mars’ Smallest Moon

Mars’ smallest moon Deimos imaged by HiRISE on Feb. 21, 2009. (NASA/JPL/University of Arizona)

Mars isn’t a planet well-known for its natural satellites but it actually does have two small moons. The larger, Phobos, is an irregularly-shaped, heavily grooved and cratered world only about 17 miles (27 km) across at its widest. It orbits Mars so closely that it completes 3 orbits every day, and isn’t even visible from some parts of the planet. But Phobos has an even smaller companion in orbit: Deimos, which at the most 7.5 miles across is half Phobos’ size. Deimos orbits Mars much further away as well, taking about 30 hours to complete one orbit.

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After 15 Years NASA and DLR Prepare to Say Goodbye to GRACE

Illustration of the twin GRACE satellites in orbit (NASA)

On March 17, 2002, a pair of satellites nicknamed “Tom” and “Jerry” launched aboard a Russian Rockot vehicle from the Plesetsk Cosmodrome in Russia. It was the start of the Gravity Recovery and Climate Experiment, aka GRACE, a partnership mission between NASA and the German space agency (DLR) to map Earth’s gravity field and how it changes over time due to the movement and variations of surface and ground water. Originally planned to be a five-year mission, GRACE has now been continuously operating in orbit for over 15 years, and has revealed much about what’s been happening to the water on—and in—our planet.

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So No New Earth Trojans, But OSIRIS-REx’s MapCam Surpassed Expectations

Asteroid 12 Victoria, imaged by NASA’s OSIRIS-REx spacecraft on Feb. 11. Credits: NASA/Goddard/University of Arizona.

Remember when I mentioned that NASA’s OSIRIS-REx spacecraft was going to be scanning for “Trojan” asteroids at Earth-Sun L4? Well the results are in and survey says: no new Trojans (besides 2010 TK7, which we already knew about.) But the search wasn’t in vain—it gave mission scientists a chance put the spacecraft’s OCAMS instruments to the test and they passed with flying colors.

In fact the MapCam camera did so well it was able to image 17 main belt asteroids from L4, some two full magnitudes dimmer than expected.

“The Earth-Trojan Asteroid Search was a significant success for the OSIRIS-REx mission,” said OSIRIS-REx principal investigator Dante Lauretta of the University of Arizona, Tucson. “In this first practical exercise of the mission’s science operations, the mission team learned so much about this spacecraft’s capabilities and flight operations that we are now ahead of the game for when we get to Bennu.”

Read the full story on the OSIRIS-REx site here: OSIRIS-REx Asteroid Search Tests Instruments, Science Team

What Is Space?

Two of my favorite comic characters contemplating the vastness of the Universe. Forever thanks to Mr. Watterson.

This is a blog post I wrote in March of 2008—a year before there was even Lights in the Dark! I’m sharing it again because it’s fun…I hope you think so too.

We’ve all seen the grade-school models of the solar system. Maybe you made one in science class. Out of painted styrofoam balls or colored construction paper. Maybe you saw one of those giant models hanging from the ceiling of your local science museum. Big colorful globes, some with rings around them, some painted swirly colors, others looking more like pitted rocks. For most people, that’s their impression of the solar system. Yellow sun in the middle, then all the different colored balls swooping around it. Some people even remember all the names from third-grade science class. Maybe even in order. (My Very Eager Mother Just Served Us Nine Pies?) If so, scratch-n-sniff stickers all around. Yum, root beer!

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This Blazing Quasar Got Wave Motion Gunned Clear Out Of Its Galaxy

Hubble image of quasar 3C 186 racing out of from its host galaxy, 8 billion light-years away from Earth. Credit: NASA, ESA, and M. Chiaberge (STScI and JHU).

Astronomers still have yet to directly capture an image of a black hole—they’re working on it—but they know where some of the largest ones are: inside the hearts of galaxies, where they power brilliant and powerful quasars whose light can be seen across the Universe. Some of these supermassive black holes (SMBs) can contain the mass of millions if not billions of Sun-sized stars and, when two galaxies happen to collide (which they often do) their respective resident SMBs can end up locked in an orbital embrace. As their spinning dance grows tighter and tighter they send out gravitational waves, rippling the very fabric of space and time itself (the LIGO experiment announced the first detection of these waves in 2016.) But if the gravitational waves are uneven, say because the two merging SMBs are of vastly different masses and/or individually spinning in different orientations (a possible but not common scenario) then the super-duper-supermassive black hole that results from the merger can end up getting one serious cosmic-scale kick after the event occurs and the waves shut off—perhaps a strong enough kick to send it hurtling out of the galaxy altogether.

That’s what astronomers think we’re witnessing here in this image from the Hubble Space Telescope.

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