Tag Archives: Tidal Lock

NASA Space Place – What It’s Like On A TRAPPIST-1 Planet

Poster’s Note: One of the many under-appreciated aspects of NASA is the extent to which it publishes quality science content for children and Ph.D.’s alike. NASA Space Place has been providing general audience articles for quite some time that are freely available for download and republishing. Your tax dollars help promote science! The following article was provided for reprinting in March, 2017.

By Marcus Woo

2013february2_spaceplaceWith seven Earth-sized planets that could harbor liquid water on their rocky, solid surfaces, the TRAPPIST-1 planetary system might feel familiar. Yet the system, recently studied by NASA’s Spitzer Space Telescope, is unmistakably alien: compact enough to fit inside Mercury’s orbit, and surrounds an ultra-cool dwarf star—not much bigger than Jupiter and much cooler than the sun.

If you stood on one of these worlds, the sky overhead would look quite different from our own. Depending on which planet you’re on, the star would appear several times bigger than the sun. You would feel its warmth, but because it shines stronger in the infrared, it would appear disproportionately dim.

“It would be a sort of an orangish-salmon color—basically close to the color of a low-wattage light bulb,” says Robert Hurt, a visualization scientist for Caltech/IPAC, a NASA partner. Due to the lack of blue light from the star, the sky would be bathed in a pastel, orange hue.

But that’s only if you’re on the light side of the planet. Because the worlds are so close to their star, they’re tidally locked so that the same side faces the star at all times, like how the Man on the Moon always watches Earth. If you’re on the planet’s dark side, you’d be enveloped in perpetual darkness—maybe a good thing if you’re an avid stargazer.

If you’re on some of the farther planets, though, the dark side might be too cold to survive. But on some of the inner planets, the dark side may be the only comfortable place, as the light side might be inhospitably hot.

On any of the middle planets, the light side would offer a dramatic view of the inner planets as crescents, appearing even bigger than the moon on closest approach. The planets only take a few days to orbit TRAPPIST-1, so from most planets, you can enjoy eclipses multiple times a week (they’d be more like transits, though, since they wouldn’t cover the whole star).

Looking away from the star on the dark side, you would see the outer-most planets in their full illuminated glory. They would be so close—only a few times the Earth-moon distance—that you could see continents, clouds, and other surface features.

The constellations in the background would appear as if someone had bumped into them, jostling the stars—a perspective skewed by the 40-light-years between TRAPPIST-1 and Earth. Orion’s belt is no longer aligned. One of his shoulders is lowered.

And, with the help of binoculars, you might even spot the sun as an inconspicuous yellow star: far, faint, but familiar.

Want to teach kids about exoplanets? Go to the NASA Space Place and see our video called, “Searching for other planets like ours”: spaceplace.nasa.gov/exoplanet-snap/

This article was provided by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

Caption: This artist’s concept allows us to imagine what it would be like to stand on the surface of the exoplanet TRAPPIST-1f, located in the TRAPPIST-1 system in the constellation Aquarius. Credit: NASA/JPL-Caltech/T. Pyle (IPAC)

About NASA Space Place

With articles, activities, crafts, games, and lesson plans, NASA Space Place encourages everyone to get excited about science and technology. Visit spaceplace.nasa.gov (facebook|twitter) to explore space and Earth science!

CNYO Brochure – A Guide For Lunar Observing

Greetings fellow astrophiles!

In preparation for upcoming 2013 lecture and observing sessions, we have put together instructional brochures to help introduce the Night Sky to attendees. The fifth of these, entitled “A Guide For Lunar Observing,” combines facts and figures about our nearest natural satellite with a map of the largest features on its “near side,” all easily visible in low-power binoculars. This brochure will be available at our combined lecture/observing sessions, but feel free to bring your own paper copy (or the PDF on a tablet – but have red acetate ready!).

Download: A Guide For Lunar Observing (v5)

NOTE: These brochures are made better by your input. If you find a problem, have a question, or have a suggestion (bearing in mind these are being kept to one two-sided piece of paper), please contact CNYO at info@cnyo.org.



A Guide For Lunar Observing

Some Interesting Facts About The Moon

620 millions years ago, the day was 21.9 hours long and one year was 400 days!

Phases Of The Moon

With respect to a fixed spot over the Earth’s surface, the Moon completes one orbit in a
sidereal month – 27 days, 7 hours, and 43 minutes.

The Blue Moon (Not Really Blue)

Since the synodic cycle of the Moon (FM to FM) is 29.5 days, a FM at the very beginning of a month will result in a FM at the end of same month.

The Man In The Moon & Other Features

The surface of the Moon shows evidence of the violent nature of the early Solar System.

The Moon – Not Just A Pretty Face!

On the side of Earth nearest the Moon, lunar gravity is strongest, pulling the water up slightly (“sublunar” high tide).

Can I See The American Flag?

There is lots of equipment left on the Moon from manned and unmanned missions, but Earth-based and many space-based telescopes do not have the resolving power to see any of it.

The Dark Side Of The Moon

The Moon’s orbital period and rotation period are the same – as it makes one trip around the Earth, it completes one spin on its axis – this is called “Tidal Lock,” and is why we only ever see one side from Earth.