Planets, Universe

Europa: Jupiter’s Icy Water-Moon

Our Sun is surrounded by a quartet of magnificent giant planets in the warmer, cooler outer parts of our Solar System. The banded behemoth, Jupiter, sticks out in the crowd as by far the biggest planet in the family of our Universe, among these enormous, alien planets. Jupiter, the “Father of Planets,” reigns in splendor from where it sits above the terrestrial planet Mars, and the Central Asteroid Belt dividing the two somewhat separate sibling species. Jupiter is known as a super-giant that may — or may not — contain a tiny stable center well-hidden beneath its thick, strong super blanket.

This gigantic gaseous world is also orbited by an impressive retinue of mostly icy moons, four of which were discovered by Galileo in 1610–Io, Europa, Ganymede, and Callisto — and named the Galilean moons in his honor. Of the four planets, thin, broken, frozen Europa sticks out as a possibly habitable alien moon-world, which is believed to have a gritty, spinning underwater ocean of life-sustaining liquid water beneath its shattered ice layer.

This idea was further confirmed in November 2019 when planetary scientists provided fresh proof that this vital element to support existence as we know it may often be fired out into space from giant geysers pocket-marking the enigmatic surface of the frozen moon. Life as we know it can not exist without liquid water and its presence indicate the possibility — although not the promise — that life exists on this remote moon-world.

Four decades ago, the first up close and personal images of Europa were obtained by a traveling Voyager spacecraft. These pictures showed brownish fractures breaking through the frozen surface of the moon, making Europa appear like a jumbo-sized shell-shaped egg. In the past forty years, missions to the outer solar system have produced sufficiently empirical data regarding Europa to render it a high priority exploration goal for NASA scientists searching for life outside Earth. 

What makes Europa so interesting is the interesting likelihood that it can contain all the ingredients required for existence to grow and develop. An international team of astronomers, led by NASA’s Goddard Space Flight Center (GSFC) in Greenbelt, Maryland, announced in November 2019 that they could confirm the presence of water in the geysers of Europa’s plumes. This they accomplished by calculating the water molecule itself directly. No one had been able to confirm the presence of water in those plumes by measuring the water molecule directly until their study. By studying Europa through the W.M., the team measured water vapor. Keck Observatory, one of the world’s largest telescopes in Hawaii.

Jupiter’s Bewitching Moon

Europa was discovered on January 8, 1610, by Galileo Galilei, along with the three other great moons of Jupiter, Io, Ganymede, and Callisto. The quartet of enchanting Jovian moons may also have been independently discovered by the German astronomer Simon Marius (1573-1625). Galileo made the first reported observation of Io and Europa on 7 January 1610. Galileo used a compact refractory telescope-one of the first optical telescopes to be used to enable his observation at the University of Padua.

However, in the initial study, owing to the poor illumination of its rudimentary telescope, Galileo was unable to differentiate Io and Europa as distinct objects. For this purpose, Galileo reported Io and Europa as a single point of light. The next night, January 8, 1610–the identification date used by the International Astronomical Union (IAU) for Europa —- Io and Europa were first detected as independent moons during Galileo ‘s observations of the Jovian planet. Historically this also marked the first time a moon was discovered around a planet other than Earth in orbit. Earth’s Moon was the Moon — the only Moon known to exist before Galileo ‘s discovery.

Europa is the smallest quartet of Galilean moons, and it is the sixth closest moon of all Jupiter’s 79 known moons to its parent-planet. It is also the sixth-largest object in our Solar System, which is just marginally bigger than the big Object on Earth. Europa is composed primarily of silicate rock, and its crust consists of water-ice. It is also expected to have an iron-nickel core, as well as a very tenuous atmosphere consisting mostly of oxygen. Even, the top of this enigmatic ice moon is riddled with streaks and cracks. But so few craters cover this frozen earth.

This indicates that the icy shell of Europa is new, as smooth crusts imply recent resurfacing which has eroded previous cratering impacts. Besides telescopes on Earth, a succession of space-probe flybys observed Europa, the first of which occurred back in the early 1970s.

Indeed, inside our Solar System, Europa boasts the smoothest surface of any recognized solid object. The apparent youth and smoothness of its icy surface suggests a water ocean slides beneath it, possibly hosting extraterrestrial forms of life. The most widely accepted model proposes that heat from tidal flexing keeps the ocean in a liquid form. This tidal flexing often causes ice displacement close to plate tectonics, and may result in the transition of essential life-sustaining chemicals from the atmosphere into the ocean below. Any geographical characteristics on Europe may be covering sea salt from a subsurface ocean.

This implies that the ocean directly communicates with the sea-floor. That observation could prove to be an important factor in determining if Europe could be habitable. In addition, the Hubble Space Telescope (HST) spotted water vapor plumes similar to those seen on Saturn’s Enceladus, which are thought to be the result of cryogeysers (icy geysers) erupting. Astronomers provided supporting evidence of water plume activity on Europa in May 2018, based on an updated analysis of data obtained from the space probe Galileo, which circled Jupiter between 1995 and 2004.

Most data on Europe are currently available for Galileo, launched in 1989. No spacecraft has yet landed on this distant icy mystery-moon, though a number of future missions are being proposed. Jupiter Icy Moon Explorer (JUICE) of the European Space Agency ( ESA) is a mission to Ganymede scheduled to be launched in 2022 and will include two Europa flybys. The new Europa Clipper from NASA is due to be launched in 2025.

With an orbital radius of approximately 670,000 kilometers, Europa circles the parent-planet within just three and a half days. Like its three other Galilean parents, Europe is locked tidally to its parent planet with one hemisphere facing Jupiter continuously, and the other one turns around. Owing to this tidal lock, the surface of Europe is sub-Jovian, from which Jupiter appeared to hang directly above the atmosphere in the European atmosphere. 

When Europe passes Jupiter, Jupiter’s tug of gravity is much greater. Europe thus extends to its parent-planet. The gravitational force of Jupiter waves as Europe shifts slightly away from Jupiter. This deterioration causes Europe to relax in a more spherical form that creates tides in the underwater ocean. Europe is continually pumped into the orbital eccentricity of its resonance from the medium motion with its sibling moon Io.

The tidal bend then reaches out and squeezes the center of Europe and provides a heat supply. This heat supply is what will hold the subsurface ocean in its liquid phase as well as push geological processes beneath it. This energy’s ultimate source is the rotation of Jupiter, which is tapped into by Io through tides on Jupiter. Then it is passed through the orbital resonance to Europe and Ganymede.

Jupiter’s Water Moon

By verifying the water vapor effect on the Europe of this enigmatic eye moon, scientists would be able to get a deeper understanding of what is happening. Astronomers will build trust in the sliding undergrowth of liquid waters by observation of water vapor that flows under the broken crust of Europe. This ocean maybe twice the size of the Earth and is located very deep under the miles thick cracked icy coat of this Moon. 

Other planetary scientists have suggested another suggestion as a potential water source for European plumes. The alternate potential route may be in the form of shallow water ice lakes not far below the shore of Europe. The idea was also created to isolate water particles from the dense ice layer of the cold moon, through Jupiter ‘s strong radiation shield. Recent research, however, has weakened the option. 

“Two out of three criteria for breathing, critical chemical elements (carbon, hydrogen, oxygen, nitrogen, phosphorous, sulphur) and energy supplies are present in the Solar System. The third-fluid water is very elusive outside this earth to locate, though scientists haven’t yet explicitly observed fluid water. Dr. Paganini is a NASA planetary scientist who performed the water identification study. 

Dr. Paganini and his team stated in their analysis in a Nov. 18, 2019 issue of the Nature Astronomy journal that they find ample water from Europe to fill a swimming pool of the Olympic scale in only minutes (5202 pounds per second). However, according to Dr. Paganini, water often existed occasionally — at least in quantity appropriate to be observed from Earth. 

“For me, not only is the first clear water detection over Europe the fascinating thing, but also the absence of water within the limits of our detection system,” he said.

Just once during 17 nights of experiments carried out between 2016 and 2017 did Dr. Paganini and his team see the low water vapor signal. The planetary scientists have detected molecules of water in the leading hemisphere of Europe, observing the Moon from Keck Observatory. The leading hemisphere is the side of a moon that is ever directed around its parent-planet in its direction. Europe, therefore, is like the Orbit of Earth itself. This is since all lunas are gravitationally connected to their stars, contributing to the orbit of the contributing hemisphere, whereas the pathway hemisphere is still rotated in the opposite direction.

In order to conduct its observation of Europe, the team of planetary researchers used the Near-Infrared Spectrograph from the Keck Observatory (NIRSPEC). NIRSPEC determines the chemical makeup, by means of the infrared radiation that they consume and release, in planetary atmospheres. Molecules such as water molecules emit specific tattle-tale infrared light frequencies when they dance with sunlight.

Prior to this latest water vapor discovery, many interesting findings were made concerning Europe. The first of these tedious results was by the NASA spacecraft Galileo. Galileo successfully measured disturbances in the magnetic field of Jupiter near Europe, while between 1995 and 2003 the spacecraft orbited the giant planet. Planetary scientists were advised that an electrically conductive fluid triggered the magnet disturbances found and that the most probable fluid was a boiling sea-salty beneath Europe’s criss-cross ice cap. When the researchers studied more closely the magnetic disturbance in 2018, proof of water vapor feathers was discovered.

In 2013, planetary scientists reported using the NASA HST to locate hydrogen (H) and oxygen (O) chemical elements, which are water components (H2O). The astronomers also noticed that hydrogen and oxygen have been detected in Europe’s atmosphere in plume-like formations. A few years later, HST was also used by other scientific teams to gather more evidence of potential feather eruptions. This party of planetary scientists collected photographs of finger-like projections that emerged as the frozen moon rotated over its banded parent-planet in the profile.

“There is a vital proof of our initial detections of atomic organisms, the first clear discovery for water vapor in Europe, demonstrating the obvious sparsity of large feathers in this frozen environment,” said Dr. Roth in Keck Observatory press release of 18 November 2019. He heads the 2013 HST survey and has co-authored this more recent research. Dr. Roth is an Astronomer and scientist from the KTH Royal Institute of Technology in Stockholm, Sweden.

In addition, Dr. Roth’s study measured only components of water on the European ice surface shell, together with these earlier findings. This ensures that it remains impossible to identify the presence of water vapor in many distant planets. Current wind turbines have little detective capacity and the distortive effects of water present on our planet’s atmosphere must be taken into account by the planetary scholars who use ground-based telescopes to search for water in deep spaces. The team of Dr. Paganini used complex computer and mathematical modeling to minimize the effect of Earth’s atmospheric water to simulate the atmospheric conditions on our planet. This was achieved by scientists so that the ambient water of the earth could be separated from the European in the NIRSPEC results.

“We have carried out careful safety checks in ground-based observation for possible contaminants, but we’re going to have to get closer to Europe to see what’s really going on,” Dr. Avi Mandell noted in the press release of the Keck Observatory on 18 November 2019. Dr. Mandell is a planetary researcher at Dr. Paganini ‘s team at the Goddard Space Flight Centre. 

Astronomers will soon be in a position to come as near as possible and Europe and answer any of the lingering puzzles about how this future tiny moon universe works outside and inside. This interesting thin, freezing environment will become clearer with the forthcoming Europa Clipper project expected to begin in the mid-2020s. For nearly fifty years, scientists have been researching Europe. These studies started with a modest photograph of a strange world that seemed to look like a large egg with a cracked shell. 

When the Clipper orbiter reaches Europe, it carries out a detailed inspection on Europe’s surface, deep interior, tenuous atmosphere, slipping surface ocean of liquid water, possibly even smaller active surface vents, following the long journey through interplanetary space. The Clipper will take photos of every feather on the mysterious surface of Europe and obtain samples of the molecules with its mass spectrometers it finds in the slender atmosphere. They would also search for a suitable location where samples might be taken from a potential lander in Europe. 

Such more work can also solve the confounding mysteries of this frozen little world of the moon, especially as to whether or not Europe is a potential refuge for life as we know it and swim in the deep dark waters of its ocean. 

Exploring The Icy Moons of Jupiter. NASA’s Europa Clipper and ESA’s JUICE