Voyager’s Incredible… Uh… Voyage: Saturn & Beyond

Hello folks.

Last week, we were talking about the Voyager 1 spacecraft & its long trip around the universe. We looked at its stop at the Jupiter system, which is made of the Solar System’s most massive planet & the 60+ moons which circle it. We spoke about the moons Europa & Io & what makes them so unique & important to our solar system.  So, let’s continue.

It took almost two years for Voyager 1 to travel to Saturn and its moons. On November 12, 1980, it arrived. It wasn’t the first to get there; those were the Pioneer probes.

Both Voyagers were vastly superior to Pioneer in many ways, but the most specific thing that set Voyager apart from the Pioneer  probes was the ability to take  high resolution photos. Most of the images taken by Voyager wouldn’t be considered high resolution by today’s standards, but for 1980, the difference was night & day. Take a look at these two photos.

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Saturn & its moons as photographed by Voyager 1.
(Photo courtesy of NASA)

P11F81

Saturn & its moons, as photographed by Pioneer 11.
(Photo used courtesy of NASA)

As you can see, the photograph taken by Voyager 1 has much more detail. This allowed scientists to scrutinize photos with ease, & lead to a number of new discoveries.

One of the most important things scientists used the new photos to study was the ring system. They came across a surprising find.  If you take a look at the image above, you’ll see that the rings are split up into many different sections, as opposed to just two or three.  Voyager also concluded that the rings change over time.

Saturn has many moons. It has 150, to be exact & 53 which are big enough to be named (including one that might actually be the Death Star). I’m only going to touch upon two of the most important, but you can read about all 53 named moons here.

On August 22, 1980, Voyager 1 flew by Enceladus (My spell check is trying to make me change it to enchiladas, but I’m not going to listen), which orbits within Saturn’s E ring. The reason Enceladus is so interesting is because of its similarity to Jupiter’s moon, Europa. It’s made of ice & the images taken by Voyager, lead scientists to believe that instead of under-crust oceans, there are pools of water, which erupt as geysers. The geysers have since been confirmed by NASA’s Cassini, which in turn confirms interior heating.  Because of this, as with Europa, Enceladus is decent a candidate for microbial life.

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Voyager image of Enceladus. Note the stretch marks like Jupiter’s moon, Europa.
(Photo courtesy of NASA)

Now to Titan. Before they could even start the Saturn phase, the flight controllers had to meet with the scientists in order to make one big decision. Choice A skiping the flyby of Titan & after exploring the other large moons of Saturn,  using the planet’s immense gravity to slingshot the craft to the outer reaches of the Solar System. It would then be on a path to make close flybys of Uranus, Neptune & Pluto. Choice B was to include Titan in the flybys. However, sending Voyager to Titan would place the craft onto a trajectory which would make it miss the other gas planets & Pluto. While it would have been cool to go see Pluto, the investigation of Titan was deemed scientifically more important.  Here’s why:

The spacecraft Pioneer 11  had reached Saturn the year before Voyager 1. During its flyby, the probe detected that Titan had unusually thick atmosphere for something the size of a natural satellite. Scientists wanted to find out what types of gasses made up Titan’s atmosphere, so Voyager was sent to find out.

It turned out that Titan’s atmosphere was not only extraordinarily thick (about 1.2 times the mass of Earth’s), but hazy. Voyager 1 discovered that the yellow haze was because the atmosphere was full of organic matter, nitrogen & methane (In 2004, the Cassini probe would discover methane rain & lakes). The condition of the atmosphere on Titan is apparently very similar to Earth’s when it was very young,  so Titan became a tool used to study what the early Earth was like.

Titan's_thick_haze_layer-picture_from_voyager1

Titan’s limb, as snapped by Voyager 1. Note the haze & the blue of the outer atmosphere.
(Photo courtesy of NASA & the Jet Propulsion Laboratory)

On December 14, 1980, Voyager 1 said, “Goodbye,” to Saturn & started its extended phase of its life. Since passing Titan meant that it wouldn’t see any of the other planets. It reached the Solar System’s escape velocity, or velocity it needs to get to so it won’t slow & fall back towards the Sun. This means, we’re not getting it back. The spacecraft was now on its way to explore the rest of the Universe.

Almost ten years went by before anything significant happened (Yes, space is that big), but on February 14, 1990, Voyager 1 turned to take a quick photo. It has since been nicknamed “The Family Portrait” & it’s the first picture of all 8 planets together. Included in the photo is a little speck, which was dubbed by Carl Sagan as “The Pale Blue Dot”.  Check out the image because it’s quite moving. If you have a hard time seeing it, click on it to make it bigger. The speck is circled for you, so you can find it.

pale_blue_dot

The Pale Blue Dot as taken by
Voyager 1
(Photo Courtesy of NASA & the Jet Propulsion Laboratory)

That tiny blue speck you’re looking at is Earth. In his book, Pale Blue Dot: A Vision of the Human Future in Space, this is what Sagan has to say about it:

Consider again that dot. 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. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love…  in the history of our species lived there… – on a mote of dust suspended in a sunbeam.
-Carl Sagan, Pale Blue Dot: A Vision of the Human Future in Space, 1997 reprint, pp. xv–xvi

This absurdly beautiful quotation really puts things into perspective, doesn’t it? You can read the entire passage here.

Eight years later, Voyager 1 overtook Pioneer 11 as the most distant object from earth, then a whole lot more nothing- well, nothing to which the general public would give their attention. However, during these long periods of travel, the JPL scientists took measurements of temperature, solar particles & cosmic rays. All this time, they continually searched for the heliopause, or the area where the solar wind is overpowered by the interstellar medium.

Voy1_8feb2012

Distance & velocity of Voyager 1 as of February, 2012. Yes, that’s almost 20 BILLION kilometers.
(Photo Courtesy of NASA)

Between 1998 & 2012, scientists announced different landmarks for Voyager 1, such as entering the heliosheath (the area in which the solar winds slow to sub sonic speeds), which were largely misunderstood by the media. Each time NASA made an announcement, at least one magazine or news company reported that Voyager exited the solar system. This is why you heard the same news report over & over.

It wasn’t until July 14, 2014, that the craft actually entered the heliopause & not until August 25 of the same year that it fully crossed it. NASA took a year to comb through the data before officially releasing it to the public. They wanted to make sure they released correct information, in order to avoid any more media confusion. Voyager 1 was officially the first man made object to exit the solar system. Let’s face it, it’s a pretty big announcement.

So, for now, Voyager is going to keep going & going… & going. Assuming it doesn’t smash into something or get picked up by some other civilization, it’ll keep on going forever, as a messenger from mankind. All we can do is keep watching & listening until the transmitters die. Until then, now that it’s in interstellar space, it will most definitely teach us new things about the Universe ever day.

Well, now you know; you’re welcome. Thanks for listening to my space nerdiness.

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