My thoughts on mission Voyager

as the title suggests I will be talking about the mission Voyager 1 and 2. I never mentioned them in separate post until today. It is also connected with my presentation I had on the contest.

What are those missions anyway?

Those are two space missions that had quests to check out furthest planets of our Solar System. Because of rare occasion, Voyager 2 was able to check out 4 planets (+ Earth).

Right now both Voyager 1 and 2 are still capable of transmitting signal because their battery working on radioactive materials is still ok, it is not much though, not pictures or something like that.

Sonda na fotografii NASA

Voyagers are twins.

Both were launched in the year of 1977 and are about 19 billion kilometers away from they Earth.

The thing is that both missions are very cool and they collected lot of data but they also have this “Voyager golden record”. It is record of “The sounds of Earth” which are voices  from various languages and also the plate contains some information on how to play it and where in Universe it was launched from.

I know that this was not the main reason for the mission to be launched but at the same time it was not really well made up.

Above you can see the information on how to play the record. How could anyone in the hell know what is this supposed to do? I mean, how can we know that aliens have similar technology like us and that five pictograms can explain how to use it!

There are also images on this thing! There is image of woman in supermarket, photo of Jupites and so on (you can check it out here).

The left circle explains in binary how fast it should be playing. Than the wave is typical frequency of the sound that should come out and under it is something called “scan triggering” (wut?). The boxes under it represent how the image is made and the circle is the first picture that should appear. The lines represent the position of Sun compared to 14 brightest pulsars out there and the two circles represent two hydrogen atoms.

Though this whole thing seems a bit dumb to me, I at least like that they included piece of uranium so that “alien” can know how long it is flying (via radioactive decay).


Moons of our Solar System: Europa

here comes the post about another moon of our Solar System. This time it is Europa. Europa the awesome moon with so white surface and those red streaks across but still the smoothest crust, Europa another Galilean moon!

Europa is very famous moon. It is also very large, sixth moon in whole Solar System and 15th object in size in whole System.
Europa-moon.jpgLike all other Galilean moons this one was also discovered by Galileo Galilei who named it Jupiter II and independently by Simon Marius who called it Europa after Zeus’s lover.

I think that Europa is very well known do to popularization of high chance of extraterrestrial life there. Probably also because of that enormous water ocean under its surface.

First of all lets look at its enormous size.

On the right you can see for comparison the size of Europa, Moon and Earth.

Mean radius of Moon is 1,737 km while for Europa it is 1,560 km. Mass of course is lower. This corresponds with density. There is 0.3 g/cm3 difference, which is not much.

Moon orbits at 380,000 km while Europa at 670,000 km. As I said in previous posts Ganymede, Io and Europa are in orbital resonance.

This means that Europa’s interior is heated by friction.

Surface of this moon is the smoothest in whole Solar System. This seems to be from the process of water running from under the crust of ice and smoothing everything out. While there are no high features, you can find there things called penitentes. Those can appear on Earth in high altitudes when snow sublimates in temperatures below zero. It creates those snowy spikes.

If you look on the first picture of whole satellite you can see that there are those red stripes.
It seems that they are created by “hot” ice flowing sometimes from under the surface. This also hints to plate tectonics on other object than Earth.
There is extreme radiation on Europa, about 5,400 mSv which is a lot and it would kill you in about a day.

Under the surface which is made of silicate rock and ice is gigantic ocean of liquid water. It is liquid because of pressure and the friction which causes its temperature to rise.
This is why astronomers think that there could be life.
There are some missions planned, one of them is very interesting and it requires some robot to land on Europa and by heating to melt down through the ice crust towards the ocean. The heat would be made by radioactive fuel.
This thing would have to be very well sterilized so it wont find its own bacteria in the ocean. Hydrobot (on the right) would be dropped there and then it would collect samples and analyze them right in the ocean.

The volume of the ocean is more than twice as much as on Earth and it may be 100 km deep.

Because of enormous tides made by Jupiter, there are water plumes of water vapor which are 200 km high. Those plumes may carry about 7,000 kg/s of material.

Europa has atmosphere but it is not very thick with pressure of 0.1 micro pascal. This atmosphere is made by ionizing radiation hitting the ground and leaving some free atoms which than become the part of atmosphere. Part of the oxygen in atmosphere is made by process called radiolysis.

To date there were already couple of missions which saw Europa from close distance, while yes, we can see Europa even from Earth because when its whole surface turned to us is lighted its apparent magnitude is 5.27 which is pretty good.

First picture taken from close distance was this one on the left. It’s Pioneer 10s picture.
Also Pioneer 11 saw him year later (1974) and after this Voyager 1 and 2 took much better pictures. First satellite to orbit Jupiter was Galileo which was working for 8 years and then it’s course was changed towards Jupiter’s atmosphere.

For now there are planned some missions that would again orbit Jupiter and collect data about its moons especially Europa because of the ocean.
For direct studying of Europa there is planned mission called Europa clipper, which would investigate its habitability and also planned is JUICE – Jupiter Icy Moon Explorer, but this one would be mostly observing Ganymede.


All pictures are from here.