Evidences of Extraterrestrial Life: Aliens

To most of all, the term Alien refers to a class of fictional characters depicted in films. But what if they were real? 

We have come up with a few mysterious happenings that took place during space explorations, indicating the presence of aliens in the Universe. These will definitely get you gosebumps!

1. Russian scientists spot something moving on a photo of Venus

The Soviet Union snapped pictures of Venus (Image: GETTY/QUEST)

Venera 13 was a probe launched by the USSR in 1981, to explore Earth’s “sister planet,” touching down a year later into the harsh atmosphere. The details of the mission were kept under wraps, as it came at a time of incredibly heightened tensions with the US, after their Apollo 11 mission put the first two men on the Moon in 1969. But, 30 years later, Russian scientist Leonid Ksanfomaliti published an article in the journal Solar System Research, claiming snaps collected contained proof of life on Venus.

Quest TV’s documentary “NASA's Unexplained Files” revealed how the story unfolded.

The series said in 2019: “A Soviet space probe reaches the hottest planet in the Solar System.

“A lander packed with a payload of cameras and scientific instruments plunges more than 48km through clouds of sulphuric acid to reach the surface.

“The probe sends back images that seem to show something moving on the surface.

“In the Cold War era, the Soviets kept the findings of the probe a closely-guarded secret.

“It takes three decades before a Russian scientist, Leonid Ksanfomaliti, reveals astonishing images from the archives.”

In one image, the Venera-13 landing probe is seen parked on the rocky Venusian foreground, and an object shaped somewhat like a crab stands inches from the probe.

In another image, also taken by Venera-13, this crab-like object appears to be in a different location.

Mr Ksanfomaliti stated in his paper: "Let's boldly suggest that the objects' morphological features would allow us to say that they are living.”

1. 1976, The Viking Mars landers detect chemical signatures indicative of life

The Viking lander

In 1976, two Viking landers became the first US spacecraft from Earth to touch down on Mars. They took the first high-resolution images of the planet, surveyed the planet's geographical features, and analyzed the geological composition of the atmosphere and surface. Perhaps most surprisingly, they also performed experiments that searched for signs of microbial life in Martian soil.

One of the tests performed on Martian soil samples by NASA’s Viking landers, which involved an analysis of a mixture of soil with radioactive carbon- labeled nutrients, hinted at chemical evidence of life.

The test reported a positive result, and the production of radioactive methane suggested that something present in the soil was metabolising the nutrients and producing radioactive gas. But other experiments conducted on board failed to find any evidence of life, so NASA declared the result a false positive.

Despite that, one of the original scientists – and others who have since re-analysed the data – still stand by the finding. They argue that the other experiments on board were ill-equipped to search for evidence of the organic molecules – a key indicator of life.

2. The unexplained extraterrestrial “Wow!” signal is detected by an Ohio State University radio telescope in 1977

The Wow! signal was a strong narrowband radio signal received on August 15, 1977 by Ohio State University's Big Ear radio telescope in the United States, then used to support the search for extraterrestrial intelligence. The signal appeared to come from the direction of the constellation Sagittarius and bore the expected hallmarks of extraterrestrial origin.

Astronomer Jerry R. Ehman discovered the anomaly a few days later while reviewing the recorded data. He was so impressed by the result that he circled the reading on the computer printout, "6EQUJ5", and wrote the comment "Wow!" on its side, leading to the event's widely used name.

The entire signal sequence lasted for the full 72-second window during which Big Ear was able to observe it, but has not been detected since, despite several subsequent attempts by Ehman and others. Many hypotheses have been advanced on the origin of the emission, including natural and human-made sources, but none of them adequately explain the signal.

Although the Wow! signal had no detectable modulation—a technique used to transmit information over radio waves—it remains the strongest candidate for an alien radio transmission ever detected.

The precise location in the sky where the signal apparently originated is uncertain due to the design of the Big Ear telescope, which featured two feed horns, each receiving a beam from slightly different directions, while following Earth's rotation. The Wow! signal was detected in one beam but not in the other, and the data was processed in such a way that it is impossible to determine which of the two horns received the signal.

3. the Allan Hills 84001 in 1984

Allan Hills 84001 (commonly abbreviated ALH84001) is a fragment of a Martian meteorite that was found in the Allan Hills in Antarctica on December 27, 1984, by a team of American meteorite hunters from the ANSMET project. Like other members of the shergottite–nakhlite–chassignite (SNC) group of meteorites, ALH84001 is thought to have originated on Mars. However, it does not fit into any of the previously discovered SNC groups. Its mass upon discovery was 1.93 kilograms (4.3 lb).

In 1996, a group of scientists claimed to have found evidence for microscopic fossils of bacteria in the meteorite, suggesting that these organisms also originated on Mars. The claims immediately made headlines worldwide, culminating in then-U.S. president Bill Clinton giving a speech about the potential discovery. These claims were controversial from the beginning, and the wider scientific community ultimately rejected the hypothesis once all the unusual features in the meteorite had been explained without requiring life to be present. Despite there being no convincing evidence of Martian life, the initial paper and the enormous scientific and public attention caused by it are considered turning points in the history of the developing science of astrobiology.

Careful analysis revealed that the rock contained organic molecules and tiny specs of the mineral magnetite, sometimes found in Earth bacteria. Under the electron microscope, NASA researchers also claimed to have spotted signs of “nanobacteria”.

4. The formulation of the Drake Equation

Dr. Frank Drake

The Drake equation is a probabilistic argument used to estimate the number of active, communicative extraterrestrial civilizations in the Milky Way galaxy.

The equation was written in 1961 by Frank Drake, not for purposes of quantifying the number of civilizations, but as a way to stimulate scientific dialogue at the first scientific meeting on the search for extraterrestrial intelligence (SETI). The equation summarizes the main concepts which scientists must contemplate when considering the question of other radio-communicative life. It is more properly thought of as an approximation rather than as a serious attempt to determine a precise number.

Criticism related to the Drake equation focuses not on the equation itself, but on the fact that the estimated values for several of its factors are highly conjectural, the combined effect being that the uncertainty associated with any derived value is so large that the equation cannot be used to draw firm conclusions.

5. 2003, Galileo mission detects Sulphur traces on Jupiter's moon Europa

Galileo Spacecraft

Galileo was an American uncrewed spacecraft that studied the planet Jupiter and its moons, as well as several other Solar System bodies. Named after the Italian astronomer Galileo Galilei, it consisted of an orbiter and an entry probe. It was delivered into Earth orbit on October 18, 1989 by Space Shuttle Atlantis. Galileo arrived at Jupiter on December 7, 1995, after gravitational assist flybys of Venus and Earth, and became the first spacecraft to orbit Jupiter. It launched the first probe into Jupiter, directly measuring its atmosphere. Despite suffering major antenna problems, Galileo achieved the first asteroid flyby, of 951 Gaspra, and discovered the first asteroid moon, Dactyl, around 243 Ida. In 1994, Galileo observed Comet Shoemaker–Levy 9's collision with Jupiter.

Jupiter's atmospheric composition and ammonia clouds were recorded, the clouds possibly created by outflows from the lower depths of the atmosphere. Io's volcanism and plasma interactions with Jupiter's atmosphere were also recorded. The data Galileo collected supported the theory of a liquid ocean under the icy surface of Europa, and there were indications of similar liquid-saltwater layers under the surfaces of Ganymede and Callisto. Ganymede was shown to possess a magnetic field and the spacecraft found new evidence for exospheres around Europa, Ganymede, and Callisto. Galileo also discovered that Jupiter's faint ring system consists of dust from impacts on the four small inner moons. The extent and structure of Jupiter's magnetosphere was also mapped.

On September 21, 2003, after 14 years in space and 8 years in the Jovian system, Galileo's mission was terminated by sending it into Jupiter's atmosphere at a speed of over 48 kilometers per second (30 mi/s), eliminating the possibility of contaminating local moons with terrestrial bacteria.

The compounds detected by the Galileo mission have been conjectured to be endogenic, most likely of cryovolcanic origin, due to their non-uniform distribution in patches. The Galileo space probe first detected the sulphur compounds, as well as revealing that this moon almost certainly has a volcanically heated and potentially habitable ocean hiding beneath a surface layer of ice. In planning future exploration of Europa there are options for sorting out the source of the surficial sulphur. For instance, one possibility is searching for the sulphur source in the context of the study of the Europa Microprobe In Situ Explorer (EMPIE), which has been framed within the Jovian Minisat Explorer Technology Reference Study (ESA). It is conceivable that sulphur may have come from the nearby moon Io, where sulphur and other volcanic elements are abundant. Secondly, volcanic eruptions in Europa's seafloor may have brought sulphur to the surface. Can waste products rising from bacterial colonies beneath the icy surface be a third alternative significant factor in the sulphur patches on the Europan surface? Provided that microorganisms on Europa have the same biochemical pathways as those on Earth, over geologic time it is possible that autochthonous microbes can add substantially to the sulphur deposits on the surface of Europa. We discuss possible interpretations of the non-water-ice elements (especially the sulphur compound mercaptan) in the context of the studies for future missions. To achieve reliable biosignatures it seems essential to go back to Europa. 

6. In 2003, Italian scientists made an hypothesis that sulphur traces on Europa might be a sign of alien life. The compounds were first detected by the Galileo space probe, along with evidence for a volcanically-warmed ocean beneath the moon’s icy crust.

The sulphur signatures look similar to the waste-products of bacteria, which get locked into the surface ice of lakes in Antarctica on Earth. The bacteria survive in the water below, and similar bacteria might also thrive below Europa’s surface, the researchers suggest. Others experts rejected the idea, suggesting that the sulphur somehow originates from the neighbouring moon Io, where it is found in abundance.

6. 2004, Methane in the Martian atmosphere indicating microbial metabolism

The reported presence of methane in the atmosphere of Mars is of interest to many geologists and astrobiologists, as methane may indicate the presence of microbial life on Mars, or a geochemical process such as volcanism or hydrothermal activity.

Since 2004, trace amounts of methane (range from 60 ppbv to under detection limit (< 0.05 ppbv)) have been reported in various missions and observational studies. 

The source of methane on Mars and the explanation for the enormous discrepancy in the observed methane concentrations are still unknown and are under study. Whenever methane is detected, it is rapidly removed from the atmosphere by an efficient, yet unknown process.

Methane (CH4) is chemically unstable in the current oxidizing atmosphere of Mars. It would quickly break down due to ultraviolet (UV) radiation from the Sun and chemical reactions with other gases. Therefore, a persistent or episodic presence of methane in the atmosphere may imply the existence of a source to continually replenish the gas.

The first evidence of methane in the atmosphere was measured by ESA's Mars Express orbiter with an instrument called the Planetary Fourier Spectrometer. In March 2004, the Mars Express science team suggested the presence of methane in the atmosphere at a concentration of about 10 ppbv.This was confirmed soon after by three ground-based telescope teams, although large differences in the abundances were measured between observations taken in 2003 and 2006. This spatial and temporal variability of the gas suggests that the methane was locally concentrated and probably seasonal. It is estimated that Mars must produce 270 ton/year of methane.

In 2011, NASA scientists reported a comprehensive search using ground-based high-resolution infrared spectroscopy for trace species (including methane) on Mars, deriving sensitive upper limits for methane (< 7 ppbv), ethane (< 0.2 ppbv), methanol (< 19 ppbv) and others (H2CO, C2H2, C2H4, N2O, NH3, HCN, CH3Cl, HCl, HO2 – all limits at ppbv levels).

7. 2004, SETI project receives  mysterious radio signals on three occasions – from the same region of space.

The search for extraterrestrial intelligence (SETI) is a collective term for scientific searches for intelligent extraterrestrial life, for example, monitoring electromagnetic radiation for signs of transmissions from civilizations on other planets.

Scientific investigation began shortly after the advent of radio in the early 1900s, and focused international efforts have been going on since the 1980s.In 2015, Stephen Hawking and Russian billionaire Yuri Milner announced a well-funded effort called Breakthrough Listen.

In February 2003, astronomers with the search for extraterrestrial intelligence (SETI) project, used a massive telescope in Puerto Rico to re-examine 200 sections of the sky which had all previously yielded unexplained radio signals. These signals had all disappeared, except for one which had become stronger.

The signal – widely thought to be the best candidate yet for an alien contact – comes from a spot between the constellations Pisces and Aries, where there are no obvious stars or planets. Curiously, the signal is at one of the frequencies that hydrogen, the most common element, absorbs and emits energy. Some astronomers believe that this is a very likely frequency at which aliens wishing to be noticed would transmit.