Moons of our Solar System: Thebe

Hi,
continuing in the promised series about moons I will today cover the satellite Thebe, this time I even have some “high resolution” pictures so keep on reading!

There are few huge craters on Thebe. (largest is Zethus with diameter of 40 km)


Thebe is another Jupiter‘s moon. It is quite smaller than Amalthea, with 100 kilometers as mean diameter. It was named for Greek nymph, in both stories I found, she was lover of Zeus (yet again) but in one she was also the daughter of Egyptian king.

It is quite similar to Amalthea, again it is tidally locked, which means that one side always turns toward Jupiter (this is also true for Moon). The surface is probably red what you can not see on black and white pictures of course. We can estimate its mass only based on the similarity with Amalthea, the value you will get is roughly 4*10^17 kilograms.

For the first time its image was taken back in 1979 by Voyager. Later, Stephen  P. Synnott found it on one picture. Four years later the name we use was first used.[1]

The fact that it is blurry wont help you much.

The above picture is the first sign of another moon, but watch out, this one is only shadow.

In background you can see some huge storms on Jupiter.

Another picture of Jupiter but this time Thebe is really visible! (Yeah it is not just filth on you monitor).

Finally, Jupiter has faint rings. These rings have to made up of something. Usually rings are created when some rocks are ripped apart by tidal forces. Also they can be fed over long periods of time be debris that leaves some moons.

Thebe has one very faint ring which is created by the second method. It is three times fainter than the ring of Amalthea which is very faint too. It has diameter of 65k-113k kilometers and it is not so thin (8400 km) as the Saturn’s rings which are even only several meters tall.

Dragallur

References: 1) 2) 3) 4) 5) 6) 7)

PS: the second and third pictures were taken from the same site and official permission should be needed only for commercial purposes, which is not me.

[1]S/1979 J 2 was the original name, though I did not decode it it probably means S=satellte 1979=the year it was found J=Jupiter 2=probably second in row with this designation.

Moons of our Solar System: Amalthea

Hi,
today I will write about another moon of Jupiter. This is surely not known to larger community because it is much smaller than the Galilean moons. I would like to say that it is beautiful as her name which I really love but the images of its surface are kind of blurry.


Totally beautiful:

Amalthea PIA02532.png

Amalthea was discovered in 1892 by E.E.Barnard (that guy after whom Barnard’s star is named after [1]). What this tells about it? Well it has to be quite big because back then the observations were not so good yet.

It was named after Amalthea, the Greek nymph who nurse Zeus, so once again it has to do with the planet it orbits.

Orbit

Amalthea if part of one ring of Jupiter, this one is called Gossamer ring. It is orbiting as 3rd satellite from Jupiter as far as we know, at the distance of roughly 181,365.84 kilometers, there is practicly no eccentricity in its movements and it take almost 12 hours to complete one spin. Some of those strange features can be explained by the moon Io.

Surface

When I said that it is not small I really meant it: 250 x 146 x 128 kilometers does some stuff. It does not have any geological activity as Io so its surface is heavily covered with craters.

There are some huge ones on its surface which were surely made by violent impact probably changing the orbit of the moon a lot, you can see them on the picture.

Otherwise there is not something too special observed about the surface of the moon, it is cold place but we still have a lot to search there.

The ring in which she orbits is made from her because Jupiter is reaping dust from its surface.

When person would stand on its surface it would see enormous Jupiter over 40° of sky. The gravity there is not so strong compared to our Moon but still great: 58m/s. Jupiter would also be very very bright, 900x brighter than Moon when it is full.

Dragallur

[1] Check out my page about Daedalus mission!