Tag Archives: Io

Voyager’s Incredible… Uh… Voyage: The Road to Jupiter

Well, it’s that time again. Here’s this week’s Bill’s Bologna.

I’m sure all of you have read the mass of articles about NASA’s announcement that Voyager 1 is now in interstellar space.

I know I spoke briefly about the Voyager probes in my 2 part You Won’t Believe How Fast it Goes post, but I’ll go into more detail here & in next week’s post. I’ll give you a little history of Voyager 1’s 36 year journey & what it has done along the way.

Okay let’s start with the basics. This is Voyager 1:

Painting of one of the Voyager probes passing Jupiter. Currently. Voyager I is the farthest man made object in the solar system & it's moving at about 39,000mph.

(Photo used courtesy of NASA)

It’s part of the Voyager program, which includes 2 spacecraft.  The other one launched, as you can imagine, is named Voyager 2. The ultimate goal of the Voyager Program was to conduct the Planetary Grand Tour, or the exploration of the outer planets &the documentation of what can be found beyond that.  Both are equipped with an array of instruments built into the spacecrafts for the scientific teams to use. You can find a list of the 5 biggest ones here, at NASA’s Jet Propulsion Laboratory’s site. Because both Voyager spacecrafts were designed to travel to distances where information could take immense amounts of time to reach Earth, the data they collect are recorded onto a magnetic tape & transmitted later, when it’s convenient for the scientists.

Since the Voyager probes were designed for deep space travel, a committee headed by Carl Sagan included golden phonograph records with each. The records contain friendly greetings, recorded in 55 different languages, traditional & popular music from around the world (including Chuck Berry’s “Johnny B. Goode”) & various sounds from nature. Along with the record, is a diagram instructing any being who might find it how to play it back. Carl Sagan’s view on this was that any other civilization smart enough to figure out the instructions & listen to our messages with interest is a civilization intelligent enough to find us on the map & contact us back.


The Golden Record from the Voyager probes  .
(Photo used courtesy of NASA.)

Sagan’s group also included over a hundred images of plants, animals, natural wonders from around the world & the for our fellow space travelers to study.

So, now that you have a grasp on what the actual craft was about, let’s talk about the trip.

Voyager 1 was launched on September 5, 1977. The launch took place 16 days after the launch of Voyager 2, which may not sound like it makes sense, but it does. Voyager 1 was sent to Jupiter on a quicker trajectory, meaning it could overtake its counterpart’s path & on December 19 of the same year, it did just that. A little over a year later, in January of 1979, Voyager 1 reached Jupiter, when it started the its mission with the planet.  Voyager 1 immediately started snapping  amazing photos of the planet & its moons. It regularly discover new things, from the onset of its exploration, up to its closest approach to the planet, at 220,000 miles (closer than our Moon is to Earth). After taking a photo of Jupiter’s moon, Io, the craft transmitted evidence of something previously unknown to anyone: Io is actively volcanic.


When scientists studied this photo, they noticed a white splotch on the surface of the planet. Upon taking a detailed look, they realized it was a giant volcano.
(Photo used courtesy of NASA)

Jupiter, being the most massive planet & second most massive object in the Solar System has a lot of gravity. You know how the Moon’s gravity pulls on the oceans to create tides? Well, scientists have since figured out that Jupiter’s gravity acts on Io’s crust in the exact same way. Since Jupiter is vastly larger than our moon, it’s gravity exerts tidal forces which stretch & compress Io as it nears & draws away from the planet. In fact, the surface of Io can be pulled by over 300 feet. This stretching of the moon creates a lot of friction, which, in turn, creates heat. That leads to Io being the most volcanically active body in the Solar System. It’ll never cool, because it’s stuck being stretched like a rubber band in Jovian orbit.

Although it didn’t spend too much time there, Voyager 1 made another important discovery about another moon, Europa. Scientists have since figured out that Europa is undergoing some of the same tidal forces Io is. Europa is thought to be made of water ice, frozen to about -260F or -160C . The theory here is that if the tidal forces are strong enough to melt rock on Io, then they should be able to warm up & melt the ice on Europa. Why is that significant? Liquid water leads to life. Even after being warmed to melt, the water is going to be extremely cold, but life is resilient. Organisms on Earth live in the coldest depths of Antarctic oceans & lakes, so just maybe on Europa…
We’ll just have to wait to land there someday first.


Europa as photographed from Voyager 1: Note how it isn’t cratered. This suggests that liquid water regularly resurfaces the moon. Those lines are thought to be stretch marks from the tidal forces that melt the ice.
(Photo used courtesy of NASA)

After discovering a wealth of information about Jupiter & its moons during the flyby, Voyager 1 headed out on its almost two year trip to Saturn.

This feels like a good place to put a bookmark. Next week, we’ll cover Saturn & what’s been happening since then. I can’t leave you without showing you that famous picture of Jupiter’s massive storm system, the Great Red Spot though, so here you go:


Voyager snapped this shot of the Great Red Spot, a storm so big, the entire Earth could fit inside…
3 times.
(Photo used courtesy of NASA)

For now, though, now you know; you’re welcome.

Leave a comment

Filed under Nerdy Science Stuff