From its history, to its composition, to the potential for colonization, and more!
Join us as we explore Europa: Jupiter's "Veiny Eyeball" Moon.
9.
The Discovery Of Europa Europa is just one of many moons around Jupiter,
and each one has a history that is all their own, including their discovery by a certain
legendary astronomer.
Europa, along with Jupiter's three other large moons, Io, Ganymede, and Callisto, was discovered
by Galileo Galilei on January 8th, 1610, and possibly independently by Simon Marius.
Though Galileo himself has called this a false claim, and because he was the first to truly
document it, he was given the credit.
Ironically, at first, Galileo couldn't separate Europa and Io in the sky because of the light
that they were giving off.
Thus, he had to wait another day and then found out that they were indeed two separate
moons.
Europa is named after Europa, daughter of the king of Tyre, a Phoenician noblewoman
in Greek mythology.
Like all the Galilean satellites, Europa is named after a lover of Zeus, the Greek counterpart
of Jupiter.
Europa was courted by Zeus and became the queen of Crete.
The naming scheme was suggested by Simon Marius, who attributed the proposal to Johannes Kepler.
The names fell out of favor for a considerable time and were not revived in general use until
the mid-20th century.
In much of the earlier astronomical literature, Europa is simply referred to by its Roman
numeral designation as Jupiter II (a system also introduced by Galileo) or as the "second
satellite of Jupiter".
In 1892, the discovery of Amalthea, whose orbit lay closer to Jupiter than those of
the Galilean moons, pushed Europa to the third position.
The Voyager probes discovered three more inner satellites in 1979, so Europa is now counted
as Jupiter's sixth satellite, though it is still referred to as Jupiter II.
And think about it, all of that struggle just to find and then name a singular moon.
8.
Size and Relation To Jupiter With an equatorial diameter of 1,940 miles
(3,100 kilometers), Europa is about 90 percent the size of Earth’s Moon.
So if we replaced our Moon with Europa, it would appear roughly the same size in the
sky as our Moon does, but brighter — much, much brighter.
Europa’s surface is made of water ice and so it reflects 5.5 times the sunlight than
our Moon does.
Europa orbits Jupiter at about 417,000 miles (671,000 kilometers) from the planet, which
itself orbits the Sun at a distance of roughly 500 million miles (780 million kilometers),
or 5.2 astronomical units (AU).
One AU is the distance from Earth to the Sun.
Light from the Sun takes about 45 minutes to reach Europa.
Because of the distance, sunlight is about 25 times fainter at Jupiter and Europa than
at Earth.
Which is important to note for several reasons.
Not the least of which is because when it comes to sunlight, you need it to be strong
to harness its energy.
Which is why solar power is feasible on Earth.
On Jupiter, or in this Europa, that wouldn't be as feasible because the fainter wouldn't
generate as much power.
Despite this though, as noted, the reflective surface does harness the light that does come
around and makes the surface much brighter.
Which has helped in part to the various probes and satellites that have tried to study it
over the years.
7.
Orbits And Rotations Europa orbits Jupiter every 3.5 days and is
locked by gravity to Jupiter, so the same hemisphere of the moon always faces the planet.
Jupiter takes about 4,333 Earth days (or about 12 Earth years) to orbit the Sun (a Jovian
year).
Jupiter’s equator (and the orbital plane of its moons) are tilted with respect to Jupiter’s
orbital path around the Sun by only 3 degrees (Earth is tilted 23.5 degrees).
This means Jupiter spins nearly upright so that the planet, as well as Europa and Jupiter’s
other dozens of moons, do not have seasons as extreme as other planets do.
Jupiter’s moons Io, Europa, and Ganymede are in what is called a resonance – every
time Ganymede orbits Jupiter once, Europa orbits twice, and Io orbits four times.
Over time, the orbits of most large satellites or planets tend to become circular, but in
the case of these three satellites, the resonance produces a forced eccentricity since the satellites
line up with each other at the same points in their orbits over and over, giving each
other a small gravitational tug that keeps their orbits from becoming circular.
Because Europa's orbit is elliptical (slightly stretched out from circular), its distance
from Jupiter varies, and the moon’s near side feels Jupiter’s gravity more strongly
than its far side.
The magnitude of this difference changes as Europa orbits, creating tides that stretch
and relax the moon’s surface.
Flexing from the tides likely creates the moon’s surface fractures.
If Europa's ocean exists, the tidal heating could also lead to volcanic or hydrothermal
activity on the seafloor, supplying nutrients that could make the ocean suitable for living
things.
6.
Surface Europa’s water-ice surface is crisscrossed
by long, linear fractures.
Based on the small number of observable craters, the surface of this moon appears to be no
more than 40 to 90 million years old, which is youthful in geologic terms (the surface
of Callisto, another of Jupiter’s moons, is estimated to be a few billion years old).
Along Europa's many fractures, and in splotchy patterns across its surface, is a reddish-brown
material whose composition is not known for certain, but likely contains salts and sulfur
compounds that have been mixed with the water ice and modified by radiation.
This surface composition may hold clues to the moon's potential as a habitable world.
NASA's Galileo spacecraft explored the Jupiter system from 1995 to 2003 and made numerous
flybys of Europa.
Galileo revealed strange pits and domes that suggest Europa’s ice layer could be slowly
churning, or convecting (cooler, denser ice sinks, while warmer less-dense ice rises)
due to heat from below.
Long, linear fractures are often only 1-2 kilometers wide but can extend for thousands
of kilometers across Europa’s surface.
Some of these fractures have built up into ridges hundreds of meters tall, while others
appear to have pulled apart into wide bands of multiple parallel fractures.
Galileo also found regions called "chaos terrain," where broken, blocky landscapes were covered
in mysterious reddish material.
In 2011, scientists studying Galileo data proposed that chaos terrains could be places
where the surface collapsed above lens-shaped lakes embedded within the ice.
5.
Atmosphere Europa has only a tenuous atmosphere of oxygen,
but in 2013, NASA announced that researchers using the Hubble Space Telescope found evidence
that Europa might be actively venting water into space.
This would mean the moon is geologically active in the present day.
If confirmed by follow-up observations, the plumes of water could be studied by future
spacecraft similar to how the Cassini sampled the plume of Saturn’s moon Enceladus.
Granted, we haven't seen the plumes in any way, not even with still imagery, but the
water vapor had to get there somehow, right?
Clearly the ice on the surface didn't melt and somehow rise up, it's too far from the
sun to do that, so how else could it have gotten up there?
Water plumes, that's how.
This discovery is changing everything we've ever thought about the moon, as well as determining
why it could be a big step towards not just finding life on other places, but how this
place could be a potential colonization spot: “Essential chemical elements (carbon, hydrogen,
oxygen, nitrogen, phosphorus, and sulfur) and sources of energy, two of three requirements
for life, are found all over the solar system.
But the third — liquid water — is somewhat hard to find beyond Earth,” said Lucas Paganini,
a NASA planetary scientist who led the water detection investigation.
“While scientists have not yet detected liquid water directly, we’ve found the next
best thing: water in vapor form.”
4.
Pop Culture Europa has been featured in short stories,
comics and novels, with perhaps the best-known being the Arthur C. Clarke novel “2010:
Odyssey Two,” which was also adapted for film.
More recently Europa was the setting for the 2013 film “Europa Report,” and it was
featured in an episode of the animated television show “Futurama.”
The moon has also been the setting or subject of several video games, including “Call
of Duty: Infinite Warfare” and “Galaga: Destination Earth.”
So clearly this moon has a lot of popularity, else it wouldn't be used this much.
And as we continue to try and expand across the universe, there's little doubt that Europa
will be home to more pop culture references as people learn even more about it.
3.
Exploration Past And Future Jupiter and its moons have been a focal point
for astronomers for literal centuries.
Ever since Galileo found some of the moons, many have tried to get closer to them and
explore their many facets.
Exploration of Europa in the modern age began with the Jupiter flybys of Pioneer 10 and
11 in 1973 and 1974 respectively.
The first closeup photos were of low resolution compared to later missions.
The two Voyager probes traveled through the Jovian system in 1979, providing more-detailed
images of Europa's icy surface.
The images caused many scientists to speculate about the possibility of a liquid ocean underneath.
Starting in 1995, the Galileo space probe orbited Jupiter for eight years, until 2003,
and provided the most detailed examination of the Galilean moons to date.
It included the "Galileo Europa Mission" and "Galileo Millennium Mission", with numerous
close flybys of Europa.
In 2007, New Horizons imaged Europa, as it flew by the Jovian system while on its way
to Pluto.
Further missions are planned to explore the moons and the back half of the solar system
as a whole.
2.
Life On Europa?
Europa is one of the few places in the solar system, aside from Earth, for which there
is very strong evidence suggesting a liquid water ocean is present today and is in contact
with rock.​ This is important because life as we know it requires three key basic "ingredients":
liquid water, an energy source, and organic compounds to use as the building blocks for
biological processes.
Europa could have all three of these ingredients, and its ocean may have existed for the whole
age of the solar system, long enough for life to begin and evolve there.
But while Europa may turn out to have the necessary ingredients for life, it may still
be lifeless.
After all, having all the ingredients to make a pie is not the same as having a pie.
What's more, given all the exploration that has been done near Europa, you would expect
us to have gotten some clues that life of any kind is there, and yet that hasn't been
the case as of yet.
If we eventually find some form of life at Europa (or Mars or Enceladus for that matter),
it may look like microbes, or maybe something more complex.
If it can be demonstrated that life formed independently in two places around the same
star, it would then be reasonable to suspect that life springs up in the universe fairly
easily once the necessary ingredients are present, and that life might be found throughout
our galaxy, and the universe.
But even the prospect of it potentially having life is enough to get some people going and
wanting to search for more clues and evidence one way or another.
If for no other reason than to help ourselves in regards to building our own life on the
moon...
1.
Colonization?
That is the question, isn't it?
With everything we know about it, do we think we can colonize a moon of Jupiter?
Technically speaking...yes, yes it does.
The idea of colonizing a moon is not far-fetched, the problem has always been whether the moon
makes sense for us to live on.
For example, we can't really live on our moon despite it being so close because it doesn't
have an atmosphere (or at least not in the sense that many picture), doesn't have enough
ice or any kind of water that we can use, and it doesn't have a natural energy source
(that we know of...) that can work in our favor to make things easier to live on it.
We can explore it fine as we've shown, but barring advances in technology, it's not a
feasible and logical place to live.
While Europa is MUCH farther away, it has things we can use to make colonization more
plausible.
For example, as noted earlier, the atmosphere may be thin (which isn't ideal) but it does
have a lot of oxygen.
Which means we could use that in our colonies to survive.
We wouldn't be able to live on the surface without protection, but the air that we could
breathe would theoretically be much easier to obtain than on other places.
Then, with the water being both in the air and on the surface via ice and underground
via the plumes, we could use that to help hydrate the colony and potentially even grow
things on the surface in the right conditions.
There are plenty of other problems that we'd have to deal with, we grant you that.
But with water vapor being on the planet we have a HUGE next step towards maybe having
a colony on another planet, and or in this case, a moon.
The problem as of right now of course is getting to Europa and trying to make it work as a
viable colony.
Help may be on the way though via the Mars colony that is trying to get made.
If we're able to make that one work, we could theoretically use that as a launching pad
to get things to Europa and start building a colony there.
At present it's just a pipe dream.
But in the future?
Anything is possible.
Especially as we continue to grow and learn more about the moon.
Thanks for watching!
What did you think of this look at Europa and what it's like?
Do you think that this is indeed a place where we can live one day?
Do you think we'll learn more about the moon that could prompt us to explore it even more?
Let us know in the comments below, be sure to subscribe, and I'll see you next time on
the channel!