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Four of the most promising alien worlds in the solar system

Four of the most promising alien worlds in the solar system 86

The Earth’s biosphere contains all the known ingredients necessary for life as we know it. In a broad sense, these are: liquid water, at least one source of energy and a list of biologically useful elements and molecules.

But the recent discovery of a nutrient in the clouds of Venus reminds us that some of these ingredients exist elsewhere in the solar system. So where are the other most promising locations for extraterrestrial life?

Mars

Mars is one of the most Earth-like worlds in the solar system. It has a 24.5-hour day, polar ice caps that expand and contract with the seasons, and a large number of surfaces that have been created by water throughout the planet’s history.

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The discovery of a lake under the south polar ice cap and methane in the Martian atmosphere (which changes with the season and even the time of day) makes Mars a very interesting candidate for life. Methane is important because it can be produced by biological processes. But the real source of methane on Mars is not yet known.

It is possible that there is life here, given the evidence that the planet once had a much more favorable environment. Today Mars has a very thin, dry atmosphere, almost entirely composed of carbon dioxide. This provides poor protection against solar and cosmic radiation. If Mars has managed to preserve some of its water reserves beneath its surface, it is possible that life could still exist.

Europe

Europa was discovered by Galileo Galilei in 1610, along with three other larger moons of Jupiter. It is slightly smaller than the Moon and orbits the gas giant at a distance of about 670,000 km every 3.5 days. Europa is constantly contracting and stretching by the competing gravitational fields of Jupiter and other Galilean moons. This process is known as tidal bending.

The moon is believed to be a geologically active world, like the Earth, because strong tidal curves heat its rocky, metallic interior and partially melt.

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Europa’s surface is a vast expanse of water ice. Many scientists think that under the frozen surface there is a layer of liquid water – a global ocean that cannot freeze due to heat and which can be more than 100 km deep.

Evidence for this ocean includes geysers erupting through cracks in the surface ice, a weak magnetic field, and chaotic surface relief that could have been deformed by ocean currents circling below. This ice sheet insulates the underground ocean from the extreme cold and vacuum of space, as well as from Jupiter’s fierce radiation belts.

At the bottom of this oceanic world, we can find hydrothermal vents and volcanoes. On Earth, such features often support very rich and diverse ecosystems.

Enceladus

Like Europa, Enceladus is an ice-covered moon with a subsurface ocean of liquid water. Enceladus revolves around Saturn and first came to the attention of scientists as a potentially habitable world after the unexpected discovery of huge geysers near the moon’s south pole.

These jets of water emerge from large cracks in the surface and, given the weak gravitational field of Enceladus, are sprayed into space. This is clear evidence of the existence of underground storage of liquid water.

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Not only water was found in these geysers, but also many organic molecules and, most importantly, tiny grains of solid silicate particles, which can only be present if the ocean’s subsurface water is in physical contact with the rocky bottom at a temperature of at least 90 ? C. This is very compelling evidence for the existence of hydrothermal vents at the bottom, providing the chemical composition necessary for life and localized energy sources.

Titan

Titan is Saturn’s largest moon and the only moon in the solar system with a solid atmosphere. It contains a thick orange haze of complex organic molecules and a methane meteorological system instead of water with seasonal rains, dry spells, and surface sand dunes created by wind.

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The atmosphere is composed primarily of nitrogen, an essential chemical used to build proteins in all known life forms. Radar observations revealed the presence of rivers and lakes of liquid methane and ethane and, possibly, the presence of cryovolcanoes – volcano-like formations that spew liquid water rather than lava. This suggests that Titan, like Europa and Enceladus, has a supply of liquid water below the surface.

At such a huge distance from the Sun, Titan’s surface temperature is -180 Celsius, which is too cold for liquid water. But the abundance of chemicals available on Titan has given rise to speculation about the possible existence of life forms – potentially with a fundamentally different chemical composition from terrestrial organisms.

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Space

KOI-5Ab, the curious planet that orbits in a system of three suns

KOI-5Ab, the curious planet that orbits in a system of three suns 103
Photo: (Caltech / R. Hurt (IPAC))

To us, the Sun alone seems perfectly normal, but our solar system is actually a strange exception.

Most stars in the Milky Way galaxy have at least one companion star. In a system 1,800 light-years away, astronomers have finally confirmed the existence of a gas giant planet orbiting stars in a triple star system.

Called KOI-5, the system is located in the constellation Cygnus, and the exoplanet was confirmed ten years after it was first detected by the Kepler space telescope.

In fact, the planet – now known as KOI-5Ab – was discovered by Kepler when it began operations back in 2009.

“KOI-5Ab was dropped because it was difficult and we had thousands of other candidates,” astronomer David Siardi of NASA’s Exoplanet Science Institute said.

“There were lighter dives than the KOI-5Ab, and every day we learned something new from Kepler, so the KOI-5 was almost forgotten.”

Exoplanet hunters tend to avoid the complexities of multi-star systems; of the more than 4,300 exoplanets confirmed to date, less than 10 percent are multi-star systems, although such systems dominate the galaxy. As a result, little is known about the properties of exoplanets in multi-star systems compared to those orbiting a lone star.

After Kepler’s discovery, Chardy and other astronomers used ground-based telescopes such as the Palomar Observatory, Keck Observatory, and the Gemini North Telescope to study the system. By 2014, they had identified two companion stars, KOI-5B and KOI-5C.

Scientists were able to establish that the planet KOI-5Ab, is a gas giant that is about half the mass of Saturn and 7 times the size of Earth, and is in a very close five-day orbit around KOI-5A. KOI-5A and KOI-5B, both of roughly the same mass as the Sun, form a relatively close binary system with an orbital period of about 30 years.

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A third star, KOI-5C, orbits the binary system at a much greater distance, with a period of about 400 years – slightly longer than Pluto’s 248-year orbit.

“By studying this system in more detail, perhaps we can understand how planets are created in the universe.”

The discovery was announced at the 237th meeting of the American Astronomical Society.

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Space

Why the universe does not fit into science

Why the universe does not fit into science 105
Photo: YouTube

Science can be compared to an artist painting what he has never seen, or to a writer describing other people’s travels: objects that he has never seen, places where he has never been. Sometimes such scientific “arts” turn out to be beautiful and interesting, but most of them will forever remain only theories, because they are beyond human capabilities.

In fact, science has the right only to speculate: how our universe appeared, how old it is, how many stars and other objects it contains.

Universe model

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How many stars are there in the sky?

With an unarmed eye, a person can see about nine thousand stars in the sky in one cloudless and moonless night. And armed with binoculars or a telescope, much more – up to several million. However, this is much less than their true number in the universe. Indeed, only in our one galaxy (the Milky Way) there are about 400 billion stars. The exact amount, of course, is not known to science. And the visible universe contains about 170 billion galaxies.

It is worth clarifying that scientists can see the universe 46 billion light years deep in all directions. And the visible (observable) universe includes the space accessible to our eyes from the moment of the Big Explosion. In other words, only this (accessible to human perception) space science refers to our universe. Science does not consider everything that follows.

It is believed that there are supposedly a ceptillion (10 to 24 degrees) stars in our universe. These are theoretical calculations based on the approximate size and age of the universe. The origin of the universe is explained by the Big Bang theory. This is why the universe is constantly expanding and the more time passes, the more complex the universe and its components become.

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It is not entirely correct to consider and perceive this scientific theory “head-on”. Scientists always claim that that explosion was not exactly an explosion, and the point that exploded was not the only one. After all, it was everywhere, because space did not exist then. And in general – everything happened quite differently from what is described in the Big Bang theory, but all other descriptions of the origin of the universe are even more incredible and inaccurate.

Separate but interconnected

That which is beyond the reach of human perception is usually discarded by science, or recognized as non-existent. Recognizing one thing, science does not want to recognize the existence of the other, although everything in our world is interconnected and is not able to exist separately – by itself.

Each object of the universe is a part of it much more than an independent, separate object.

Any person, like any material object of our world, consists of components: organs, cells, molecules, atoms. And each of its constituent parts can represent the whole world. Separate, and at the same time connected with all the others.

However, science, as a rule, perceives all the components of the universe – people, animals, plants, objects, the Earth, the Sun, other planets and stars – as separate subjects, thereby limiting itself.

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Even what is considered the visible universe, one of the atoms of which could be called our solar system, is not subject to the boundaries of human perception. But perhaps the atom is an exaggeration, and our solar system is not even an atom, but one of its elements!

How, being so far from the truth, can one reason about something with the degree of probability with which science tries to reason about the origin of the universe?

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Space

An unexplained wobble shifts the poles of Mars

An unexplained wobble shifts the poles of Mars 109

The red planet sways from side to side like a whirligig when it loses speed. The new study allowed scientists to notice that the poles of Mars deviate slightly from the axis of rotation of the planet. On average, they move 10 cm from the center with a period of 200 days.

Such changes are called the Chandler Oscillations  – after the American astronomer Seth Chandler, who discovered them in 1891. Previously, they were only seen on Earth. It is known that the displacement of the poles of rotation of our planet occurs with a period of 433 days, while the amplitude reaches 15 meters. There is no exact answer why this is happening. It is believed that the fluctuations are influenced by processes in the ocean and the Earth’s atmosphere.

Chandler’s wobbles on Mars are equally perplexing. The authors of the study discovered them by comparing data from 18 years of studying the planet. The information was obtained thanks to three spacecraft that orbit the Red Planet: Mars Odyssey, Mars Reconnaissance Orbiter and Mars Global Surveyor. 

Since Mars has no oceans, it is likely that the Red Planet’s wobbly rotation is due to changes in atmospheric pressure. This is the first explanation that researchers have shared. In the future, there should be new details about the fluctuations that have so interested the scientific community.

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