Signs of alien life on Mars could have been wiped out by space radiation: Scientists say finding ET may be harder than we think

• Amino acids are potential signs of past life that might be found on Mars
• But new research has shown they are unlikely to be on planet's surface
• They were probably destroyed by space radiation, according to study
• Future missions will have to dig deeper into Mars' surface to find clues 

By ABIGAIL BEALL FOR MAILONLINE

Mars is among a group of planets and moons in our solar system considered promising candidates for hosting, or having once hosted, alien life.

But signs of this life in the solar system may be harder to find than previously thought.

Any relics left over on the surface of the planet are likely to have been wiped out by powerful space radiation, according to new research.

Our neighbouring planet Mars could have been covered in vast salty oceans (artist's impression pictured) that would have been ideal for life to form. According to a new study, the signs of this life might be more difficult to find than previously thought, because of the harmful effects of space radiation 

Mars is considered two of the most likely places for signs of past life to be found in our solar system because it is the planet that most closely resembles our own.

The red planet once hosted vast oceans on its surface, which is considered one of the most vital properties necessary for life to thrive.

But new research is suggesting signs of this life might more difficult to find, because they could be destroyed by the harsh radiation in space more quickly than previously thought.

Amino acids, the building blocks of proteins, are one of the signs researchers are hoping to find. 

Previous research suggested amino acids could survive for up to 1 billion years under Martian conditions. 

But Dr Alexander Pavlov, space scientist at Nasa's Goddard Space Flight Center in Maryland, and colleagues conducted new research and found the majority of amino acids were likely to be destroyed in 20 million years. 

The 'search for the extinct life on Mars is based on the assumption that some original complex organic molecules would be able to survive for hundreds of millions - billions of years in the ancient Martian outcrops' according to the study. 

WHAT ARE THESE COSMIC RAYS? 

The Earth is constantly bombarded by high energy particles like protons, electrons and atomic nuclei. These particles make up the so-called 'cosmic radiation'.

These 'cosmic rays' are electrically charged, and are hence strongly deflected by the interstellar magnetic fields that pervade our galaxy.

This means the path they have travelled through the cosmos to reach us is so random that we have no idea what made them, so they have baffled scientists for more than a century. 

The Earth's thick atmosphere acts as a shield from the rays.

But modern Mars has a thin atmosphere and Europa has virtually no atmosphere at all. 

Both worlds are bombarded by high levels of radiation, which could spell doom for any fossils that may have once existed on the worlds' surfaces.

The Earth is constantly bombarded by high energy particles like protons, electrons and atomic nuclei. These particles make up the so-called 'cosmic radiation'. These 'cosmic rays' are electrically charged, and are hence strongly deflected by the interstellar magnetic fields that pervade our galaxy

'More than 80 percent of the amino acids are destroyed for dosages of 1 megagray, which is equivalent to 20 million years,' Dr Pavlov said during a presentation at a conference, according to Live Science. 

'If we're going for ancient biomarkers, that's a very big problem.'

Mars' ocean is thought to have existed around 3.4 billion years ago, when life was first starting to form on our own planet. 

But Dr Pavlov's team mixed the amino acids with rocky material similar to that found on Mars, and found all the amino acids were degraded by radiation in as few as 50 million years.

This means Mars rovers would have to dig deeper to find amino acids that might have been shielded from the radiation.

'We are extremely unlikely to find primitive amino acid molecules in the top 1 metre [3.3 feet] [of the crust], due to cosmic rays,' Dr Pavlov said. 'It would be critical to provide missions with 2-metre [6.6 feet] drilling capabilities, or chose landing sights with freshly exposed rocks.'

Mars rovers like Nasa's Curiosity, shown, will have to dig deeper to find amino acids that might have been shielded from the radiation. Future missions would have to have 6.6 feet (2 metre) drilling capabilities, or chose landing sights with freshly exposed rocks, the researchers have said

A separate study focusing on Jupiter's moon Europa also concluded the surface of the moon is an unlikely place for signs of life to survive.

Simulating the conditions on Europa's surface, the researchers found the moon's radiation dosages were comparable to those on Mars.

'Radiation is going to play a major role at Europa in the top few meters — actually, dare I say, dozen meters — of Europa's surface,' said Luis Teodoro, a planetary scientist at Nasa's Ames Research Center in California, speaking at the same conference.

He said his simulations suggest microbes found in some of Earth's harshest environments would survive no more than 150,000 years in the top 3.3 feet (1 m) of Europa's icy crust.

Organic biomarkers buried within 3.3 feet  (1 metre) of the surface would last only 1 to 2 million years, he said.

'If we want to put a lander on the surface of Europa to check if life is there, we most likely are going to see something destroyed — mangled materials, mainly organics — from this huge dosage of radiation,' he said.

With a liquid layer located just a few miles underground, the ground on Europa refreezes where an impact happens, creating a fractured terrain with young scars on its plains, as seen in this image

JUPITER'S ICY MOON EUROPA 

Jupiter's icy moon Europa is slightly smaller than Earth's moon. 

Europa orbits Jupiter every 3.5 days and is tidally locked - just like Earth's Moon - so that the same side of Europa faces Jupiter at all times.

It is thought to have an iron core, a rocky mantle and a surface ocean of salty water, like Earth. 

Unlike on Earth, however, this ocean is deep enough to cover the whole surface of Europa, and being far from the sun, the ocean surface is globally frozen over.

Many experts believe the hidden ocean surrounding Europa, warmed by powerful tidal forces caused by Jupiter's gravity, may have conditions favourable for life. 

Alien Ocean: NASA’s Mission to Europa

https://youtu.be/GqTaDCt_F1Y

NASA - Next Target Is The Alien Ocean World Of Europa

https://youtu.be/5D4uJh8hjdw

Nasa secrets revealed 2015 - Alien Ocean: NASA’s Mission to Europa new

https://youtu.be/UN0IEc2eXUw

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