Tag Archives: Io

NASA Space Place – Snowy Worlds Beyond Earth

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 December, 2017.

The Space Place article format has changed recently, including more embedded images. To simplify the posting process, a PDF version of the article is provided below, with a snippet of the article reproduced below it.

Download as PDF: Snowy Worlds Beyond Earth

By Linda Hermans-Killiam


There are many places on Earth where it snows, but did you know it snows on other worlds, too? Here are just a few of the places where you might find snow beyond Earth:

A Moon of Saturn: Enceladus

Saturn’s moon, Enceladus, has geysers that shoot water vapor out into space. There it freezes and falls back to the surface as snow. Some of the ice also escapes Enceladus to become part of Saturn’s rings. The water vapor comes from a heated ocean which lies beneath the moon’s icy surface. (Jupiter’s moon Europa is also an icy world with a liquid ocean below the frozen surface.) All of this ice and snow make Enceladus one of the brightest objects in our solar system.

Caption: Enceladus as viewed from NASA’s Cassini spacecraft. Credit: NASA

Want to learn more about weather on other planets? Check out NASA Space Place: spaceplace.nasa.gov/planet-weather

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

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!

A Rare Triple-Transit Across Jupiter Tonight – 1:28 a.m. to 2:12 a.m. EST – Early Live Observing At New Moon Telescopes & Livestream’ed From The Griffith Observatory

Greetings fellow astrophiles!

If the sight of the green fuzzy blob that is Comet Lovejoy has excited you these past few weeks, then tonight will knock your foot-warmer’ed socks off. A rare triple-transit is happening early-early this morning across the surface of Jupiter, when the moons Io, Callisto, and Europa will all have their shadows cast on Jupiter’s surface at the same time for about 24 minutes. Until we get some really-really good telescopes for the professional amateur, Jupiter is the only planet in the solar system for which triple transits are visible from Earth’s surface (because its four Galilean satellites – Io, Europa, Ganymede, and Callisto are big enough to case prominent shadows). Those who sleep through tonight’s will have to hang out until March 20th of 2032 (or buy a space shuttle from NASA surplus).

The triplet transit across Jupiter, courtesy of the Griffith Observatory youtube channel.

For those willing to brave the not-as-cold-as-recently temperatures of West Monroe tonight, Ryan Goodson has graciously offered his clear zenith at New Moon Telescope HQ starting around 9:30 p.m. – early enough to catch some of the night’s best objects and see the first shadow, that of Callisto, hit Jupiter’s surface before those with sleep schedules retire for the evening. Provided the CNY skies hold out, we might even stay long enough to catch the triple’s beginning.

For those wanting directions, please contact Ryan Goodson (ryan@newmoontelescopes.com) or myself (Contact Page or info@cnyo.org).


Ryan Goodson and the skies above NMT HQ, including a bright Jupiter above and Comet Lovejoy just at the treeline at right. Click for a larger view.

For those convinced that the rest of us are crazy for attempting anything like this before the first Spring thaw, I am pleased to report that the Griffith Observatory will be streaming the event real-time from their livestream.com channel (which means you can always watch it in the morning over iced coffee). You can watch it below right on the CNYO website or head on over to the Griffith Observatory livestream channel at new.livestream.com/GriffithObservatoryTV.

The timings for the event are listed below as provided direct from space.com (which I encourage you to check out for more details), all times Eastern.

10:11 p.m. Callisto’s shadow enters disk

11:35 p.m. Io’s shadow enters disk

11:55 p.m. Io enters disk

1:19 a.m. Callisto enters disk

1:28 a.m. Europa’s shadow enters disk, triple shadow transit begins

1:52 a.m. Io’s shadow leaves disk, triple shadow transit ends

2:08 a.m. Europa enters disk, triple satellite transit begins

2:12 a.m. Io leaves disk, triple satellite transit ends

3:00 a.m. Callisto’s shadow leaves disk

4:22 a.m. Europa’s shadow leaves disk

5:02 a.m. Europa leaves disk

6:02 a.m. Callisto leaves disk

NASA Space Place – The Most Volcanically Active Place Is Out-Of-This-World!

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 November, 2013.

By Dr. Ethan Siegel

2013february2_spaceplaceVolcanoes are some of the most powerful and destructive natural phenomena, yet they’re a vital part of shaping the planetary landscape of worlds small and large. Here on Earth, the largest of the rocky bodies in our Solar System, there’s a tremendous source of heat coming from our planet’s interior, from a mix of gravitational contraction and heavy, radioactive elements decaying. Our planet consistently outputs a tremendous amount of energy from this process, nearly three times the global power production from all sources of fuel. Because the surface-area-to-mass ratio of our planet (like all large rocky worlds) is small, that energy has a hard time escaping, building-up and releasing sporadically in catastrophic events: volcanoes and earthquakes!

Yet volcanoes occur on worlds that you might never expect, like the tiny moon Io, orbiting Jupiter. With just 1.5% the mass of Earth despite being more than one quarter of the Earth’s diameter, Io seems like an unlikely candidate for volcanoes, as 4.5 billion years is more than enough time for it to have cooled and become stable. Yet Io is anything but stable, as an abundance of volcanic eruptions were predicted before we ever got a chance to view it up close. When the Voyager 1 spacecraft visited, it found no impact craters on Io, but instead hundreds of volcanic calderas, including actual eruptions with plumes 300 kilometers high! Subsequently, Voyager 2, Galileo, and a myriad of telescope observations found that these eruptions change rapidly on Io’s surface.

Where does the energy for all this come from? From the combined tidal forces exerted by Jupiter and the outer Jovian moons. On Earth, the gravity from the Sun and Moon causes the ocean tides to raise-and-lower by one-to-two meters, on average, far too small to cause any heating. Io has no oceans, yet the tidal forces acting on it cause the world itself to stretch and bend by an astonishing 100 meters at a time! This causes not only cracking and fissures, but also heats up the interior of the planet, the same way that rapidly bending a piece of metal back-and-forth causes it to heat up internally. When a path to the surface opens up, that internal heat escapes through quiescent lava flows and catastrophic volcanic eruptions! The hottest spots on Io’s surface reach 1,200 °C (2,000 °F); compared to the average surface temperature of 110 Kelvin (-163 °C / -261 °F), Io is home to the most extreme temperature differences from location-to-location outside of the Sun.

Just by orbiting where it does, Io gets distorted, heats up, and erupts, making it the most volcanically active world in the entire Solar System! Other moons around gas giants have spectacular eruptions, too (like Enceladus around Saturn), but no world has its surface shaped by volcanic activity quite like Jupiter’s innermost moon, Io!

Learn more about Galileo’s mission to Jupiter: solarsystem.nasa.gov/galileo/.

Kids can explore the many volcanoes of our solar system using the Space Place’s Space Volcano Explorer: spaceplace.nasa.gov/volcanoes/.

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


Caption: Io. Image credit: NASA / JPL-Caltech, via the Galileo spacecraft.

About NASA Space Place

The goal of the NASA Space Place is “to inform, inspire, and involve children in the excitement of science, technology, and space exploration.” More information is available at their website: http://spaceplace.nasa.gov/

CNYO Observing Log: Baltimore Woods, 9 February 2013

Ryan Goodson, Larry Slosberg, and I joined Bob Piekiel for his monthly New Moon observing session at Baltimore Woods on his weather-alternate session (having lost Friday’s session to Snow Storm Nemo). What started as a remarkably cold session, which then progressed to a bitterly cold session, and then finally to an intolerably cold session (forcing us to close shop up around 8:30 p.m.), still provided some excellent views of the Winter Sky, including the Solar System‘s largest planet Jupiter right between the Hyades and Pleiades.

For those who haven’t ventured for a session, the view from the Baltimore Woods parking lot includes a clear zenith (what luck!), a tree to the North that extends almost up to Polaris (so one must walk around it to get the view of constellations below our North Star), low-lying trees to the West, then the warm orange glow (the only thing warm on the 9th) of Baldwinsville and Syracuse to the East-Southeast. As we’re mid-winter, the evening observing was obstructed occasionally by blindingly bright snowmobiles (but one had plenty of lead time to take cover).

The evening started early with a fly-by of the yellow-orange ball that is (from the ground, anyway) the International Space Station (ISS), right on schedule with the predictions from heavens-above.com:

Date Brightness Start Highest point End Pass type
[Mag] Time Alt. Az. Time Alt. Az. Time Alt. Az.
09 Feb -3.3 18:55:57 10° SW 18:59:16 68° SE 18:59:56 51° E Visible

Reaching a total session count of eight, the evening included several observations of Jupiter, noting specifically how quickly Io rushed from Jupiter as even 10 minute intervals progressed (the slow cooling of mirrors resulted in many returns of increasingly crisp views). A comparison of eye piece magnifications and field-of-views was performed with the Pleiades in Bob’s 11″ Schmidt–Cassegrain and Ryan’s 16″ NMT Dob. In both cases, one my my favorite doubles, Tyc1800-1961-1 (blue) and Tyc1800-1974-1 (orange), jumped right out from the center of the tea cup. The lesson learned from such an exercise is that magnification is not the key to observational astronomy – it is seeing all that you want to see in the field of view that is key to enjoying the Night Sky.

A second highlight of the evening included M35, an open cluster in Gemini that, at 2,800 light years away, still covers an area the size of the Full Moon. Clearly visible as a slight “smudge” in the upper-left corner of the eyepiece (so the lower-right corner of M35) at low magnification is the compact open cluster NGC 2158.

After Jupiter, the night belonged to the massive Orion Nebula (M42), a hydrogen cloud doubling as a stellar nursery. At a magnitude of +4.0, the fuzzy patch in Orion’s Belt is visible to the Naked Eye, increasing in density with small binoculars, and leading to magnificent views of filamentous nebulosity at low magnification in both telescopes. The splitting of the main binaries in Trapezium was trivial in Ryan’s 16″ NMT Dob even without a completely cooled mirror.

I noted to Ryan that, given the usual CNY winter conditions, “It’s a rarity to see Pegasus in the West.” The quintet of Sirius, Orion’s Belt, the Hyades, Jupiter, and the Pleiades was worth the visit with or without equipment. After 90 minutes of observing in cold, continually patchy skies, the temperature dropped precipitously, instigating a rapid retreat and scope packing by all attendees. The lessons learned – your gloves are never thick enough & always have a headlamp in the car for the end of the evening!