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This Beautiful Webcomic Shows Why Our “Mathematical Skies” Have Not Lost Their Wonder

Our newfound knowledge of

Our newfound knowledge of “what’s out there” has not reduced its fascination (Image © Boulet)

People of past civilizations had their own ideas of what the stars in the night sky are… distant campfires, lights shining through holes in a vast blanket covering the Earth, deceased ancestors, countless and constantly-traveling gods… whether or not they really believed these stories or if they were just tales to inspire poets and provide entertainment on dark nights is hard to tell. But one thing is for certain: we now know what those points of light really are, thanks to the past several centuries of hard work by astronomers, scientists, and engineers, and although that may make ancient tales about the stars obsolete it certainly doesn’t reduce the inherent wonder and beauty of the night sky – if anything, it has increased it many times over.

Recently French cartoonist Boulet illustrated his own lifelong fascination with space in a webcomic published on his site. In a Dante-esque fashion he takes the figure of French singer Georges Brassens on a trip across the solar system, showing him why science and rational thought have not chased away fascination and beauty along with “the old gods”, as Brassens sang in a 1964 song (which I was not familiar with.) “Eureka” was not a death sentence for wonder!

It’s a really beautiful comic, with brilliant timing and subtle animations to highlight keep points along the way. Don’t scroll too fast.

You can view the full scrollable webcomic here in English and/et ici en Français.

HT to Laurie C. for the link.

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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When a Comet Met Ganymede

Galileo image of a crater chain on Jupiter's moon Ganymede (NASA/JPL)

Galileo image of a crater chain on Jupiter’s moon Ganymede (NASA/JPL)

Captured by NASA’s Galileo spacecraft on April 5, 1997, this image shows Enki Catena, a 161.3-km (100-mile) long crater chain on the surface of Jupiter’s moon Ganymede. Named after the Sumerian god of fresh water, Enki Catena is thought to have been formed when a comet approached too close to Jupiter and was torn into 13 pieces, each impacting Ganymede in rapid succession… sort of a miniature version of what occurred in 1994 with comet Shoemaker-Levy 9.

Ganymede is not only Jupiter’s largest moon but also the largest moon in the Solar System. At 5,268 km (3,273 miles) across it is larger than Pluto and Mercury, and is the only moon that generates its own magnetosphere.

Launched in October 1989, Galileo arrived at Jupiter in December 1995 and orbited the giant planet 34 times before ending its mission with a dive into Jupiter’s atmosphere on September 21, 2003. Learn more about Galileo mission highlights here.


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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Eppur Si Muove: Galileo’s Big Night

Note: This is an edited repost of an article from 2014.
Jupiter and the fours "Galilean moons" Europa, Io, Callisto, and Ganymede. (Jan Sandberg/

Jupiter and the four “Galilean moons” Europa, Io, Callisto, and Ganymede. (Jan Sandberg/

405 years ago tonight, January 7, 1610, the Pisan astronomer Galileo Galilei looked up at a bright Jupiter at opposition through his handmade telescope and saw three little “stars” next to it, which piqued his natural scientific curiosity. He soon realized that these little objects weren’t stars at all but rather moons orbiting the giant planet (and, most importantly, not Earth). Further observations over the next few nights showed that the planet wasn’t moving relative to the little “stars” as it should if they were indeed background stars, and in fact the smaller bodies (of which he soon saw four) were moving along with Jupiter each in its own little orbit. This revelation helped change our entire view of the Solar System, causing no end of trouble for Galileo (as the Church didn’t appreciate data contradicting their conveniently Earth-centered Universe) but also opening the door for the discovery of many more moons around other planets.

Today Jupiter is now known to have at least 50 moons, with possibly as many as 67!

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Jupiter’s Moons Make Ghostly Auroral “Footprints”

UV image of Jupiter taken with the Hubble Space Telescope Imaging Spectrograph (STIS) on November 26, 1998. (NASA/ESA, John Clarke (University of Michigan))

Aurorae seen in a UV image of Jupiter taken with the Hubble Space Telescope Imaging Spectrograph (STIS) on November 26, 1998. (Credit: NASA and the Hubble Heritage Team)

We have all marveled at incredible photos and time-lapse videos of Earth’s auroral displays, captured by talented photographers that have braved the frigid nighttime temperatures of remote high-latitude locations as well as by those privileged few living in orbit aboard the International Space Station. But our planet isn’t the only one with curtains of light crowning its poles – aurorae have been observed on Jupiter, Saturn, Uranus, and Neptune as well (and Venus may even have them too.) While we know that these light shows are caused by interactions between atoms in planets’ upper atmospheres and charged particles from the Sun that get caught up in magnetic fields focusing out from around the poles, Jupiter in particular is known to have a peculiar additional type of auroral feature, created by the moons that orbit it.

The image above, captured by the Hubble Space Telescope Imaging Spectrograph (STIS) on November 26, 1998, shows Jupiter’s north polar region in ultraviolet light. The planet’s energetic aurorae can be seen wrapping around its pole in wavy circular arcs, just like Earth’s does. But there are also several bright spots that aren’t due to solar activity but are instead the “footprints” of three of its largest moons: Ganymede, Europa, and Io.

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