Curiosity Sees Phobos Transit . . . After Sundown

April 4, 2019 - Comment

NASA’s Curiosity rover simply spied transits of each Martian moons throughout the face of the Solar — together with one which occurred after the Solar had set. Phobos, transiting throughout the face of the Solar on Sol 2,359 (Tuesday, March 26th). NASA / JPL-Caltech / MSSS / Sequence: Dave Dickinson In Andy Weir’s ebook The


NASA’s Curiosity rover simply spied transits of each Martian moons throughout the face of the Solar — together with one which occurred after the Solar had set.

Phobos Shadow

Phobos, transiting throughout the face of the Solar on Sol 2,359 (Tuesday, March 26th).
NASA / JPL-Caltech / MSSS / Sequence: Dave Dickinson

In Andy Weir’s ebook The Martian, stranded astronaut Mark Watney makes use of the rising and setting instances of the Martian moons, Phobos and Deimos, as a tough type of “lifeless reckoning” to assist him discover his method. This previous week, an astute observer combing by means of latest photos from the Curiosity rover turned up an equally attention-grabbing sight: the shadow of the innermost moon Phobos because it slid silently throughout the face of the Solar — after the Solar had simply set.

Solely days earlier than, Curiosity had additionally caught a transit of Deimos, and now NASA has launched a set of photos from each photo voltaic transits as seen from the rover’s perspective, utilizing photo voltaic filters connected to Curiosity’s Mastcam.

Deimos transit

Tiny Deimos marches throughout the face of the Solar, as seen from the floor of Mars.
NASA / JPL-Caltech / MSSS

“Extra observations over time assist pin down the small print of every orbit,” says Mark Lemmon (House Science Institute / Texas A&M College) in a latest press launch. “These orbits change on a regular basis in response to the gravitational pull of Mars, Jupiter, and even every Martian moon pulling on the opposite.”

Curiosity has noticed such transits earlier than, however that is the primary time it has seen the shadow of Phobos cross the sky after Martian sundown.

Chasing Moon Shadows on Mars

This distinctive phenomenon was first observed and posted by person FredK on the Unmanned Spaceflight Discussion board on March 26th. The pictures, taken by Curiosity’s proper Navcam, appeared to point out a shadow crossing the sky, in all probability solid by means of a skinny layer of suspended mud within the tenuous Martian environment.

This piqued the curiosity of Jet Propulsion Laboratory’s Doug Ellison, who processed and stacked a few of the photos after which posted the thread on Twitter (he is @doug_ellison). NASA later launched a proper sequence of the unbelievable sight:

Phobos Shadow

The shadow of Phobos slides off to the the suitable after sundown, on this view from Curiosity on Sol 2,358.
NASA / JPL / Caltech

“We knew it was coming (we deliberate the remark to seize it in spite of everything),” says Ellison, “nevertheless it was superb to see somebody on the market determine it out… it was fairly refined within the uncooked public .jpgs!”

Now, Curiosity is not any stranger to Phobos’s irregular transits. (We check with them as transits relatively than eclipses, as a result of the moon is on common 12 arcminutes throughout and by no means absolutely covers the 20.5-arcminute-diameter Solar, as seen from the Martian floor.) NASA engineers have even used observations of such occasions to pin down the exact orbits for the moon. Alternative has snapped transits of tiny Deimos previously as effectively.

What’s distinctive this time is that the ultimate sequence catches the occasion after native sundown. Ellison ran the circumstances for the rover for round four:49 Common Time (UT) on March 26th and confirmed the transit. Heck, the shadow even seems eerily like a redux of the Moon’s shadow seen crossing the sky throughout a complete photo voltaic eclipse on Earth.

eclipse

The shadow of Earth’s Moon sliding throughout the sky as seen throughout the 2017 whole photo voltaic eclipse.
Alan Dyer / Superb Sky

Phobos and its shadow have flip up in different photos, too: NASA’s Mars World Surveyor orbiter has seen the moon’s misshapen shadow flitting throughout the Martian panorama.

Phobos Shadow

The shadow of Phobos, as seen by Mars World Surveyor in 2000.
NASA / JPL / MSSS

And Mars Perception has additionally just lately documented a definite darkening when Phobos transited the noon Solar as seen from the lander’s location:

Phobos shadow

The shadow of Phobos dims the view over the Perception touchdown website.
NASA / JPL-Caltech

Perception is even anticipated to detect small land tides raised by Phobos because it passes overhead.

Phobos orbits Mars as soon as each 7 hours and 39 minutes from simply three,721 miles (5,989 kilometers) above the Martian floor — the closest any moon orbits its host planet within the photo voltaic system. As a result of it orbits quicker than the planet rotates, a Mars-based observer will see Phobos rise within the west and set within the east — a very weird sight.

The post-sunset transit is a testomony to what keen-eyed observers can flip up in planetary imagery, with a little bit talent and endurance. Maybe sooner or later human eyes will witness the refined shadow of Phobos sliding overhead. Our greatest wager although, is to journey to the slopes of Elysium Mons, the place on November 10, 2084, one might spy Phobos, Earth, and the Moon transit the Solar on the identical time.

After all, there is a slight little bit of uncertainty in calculating such a far-off occasion; we promise to rerun the simulation come 2083. Let’s examine, by then I will be . . .



Supply hyperlink

Comments

Comments are disabled for this post.