Martian Life, if it Exists, Could Still Be Present Underground

 

Earth sits right in the middle of our sun’s habitable zone, the region where the heat of the star allows liquid water to exist on the surface of a planet. Mars orbits at the outer edge of this zone. Astronomers generally agree that Mars once sported rivers, lakes and, oceans. Mars reached such life-supporting conditions even before Earth. Its smaller size allowed it to cool more quickly from the heat of formation.

But Mars’ smaller size also allowed its core to cool and solidify long ago, killing its magnetic field. Without that magnetic field, solar radiation slowly knocked the atmosphere of Mars into space. Lacking an atmosphere, Mars couldn’t trap the sun’s heat, so it turned cold. Nighttime temperatures routinely drop to near 100 degrees below zero.

But, prior to the loss of its atmosphere, Mars sported conditions that could have supported life. That is no longer true of the surface of Mars. The thin atmosphere can no longer warm the surface of Mars nor protect it from cosmic radiation. Many scientists, including astrophysicist and research scientist Dimitra Atri, from the Center for Space Science at NYU Abu Dhabi, believe that conditions not far below the surface could potentially support life, albeit only at the bacterial level.

In 2022, the European Space Agency and Roscosmos, the Russian space organization, will launch the ExoMars craft, which includes the Rosiland Franklin rover. Atri says that rover will have the ability to detect any such subsurface life on the Red Planet. "It is exciting to contemplate that life could survive in such a harsh environment, as few as two meters (six feet) below the surface of Mars," said Atri. "When the Rosalind Franklin rover onboard the ExoMars mission, equipped with a subsurface drill, is launched in 2022, it will be well-suited to detect extant microbial life."

                           ExoMars Rosalind Franklin rover, Credit European Space Agency (ESA).

If we find life on Mars, it will indicate that life forms easily, given that life developed on both planets in our solar system capable of supporting it. That tells astronomers that perhaps many of the tens of billions of Earth-like planets in our Milky Way galaxy likely did, too.

     Each month, I write an astronomy-related column piece for the Oklahoman newspaper. On the following day, I post that same column to my blog page.

     This is reprinted by permission from the Oklahoman and www.newsok.com.

Life Below Earths Ocean Floor Give Scientists Hope for Finding Life on Mars

Ten years ago, scientists from the University of Tokyo, Japan, led an expedition to drill into rock 400 feet below the ocean floor. They have been studying the various rock samples, ranging in age from thirteen million years to 104 million years, ever since. Theses ocean rocks formed when undersea volcanoes spewed out lava which cooled into fractured rock and became buried under ocean sediment. The cracks filled with clays from the ocean floor.

The scientists knew that rocks beneath the surface of dry land were home to bacteria, and they looked for bacteria living in the ocean rocks. After intense study, with some missteps along the way, they finally found dense bacterial colonies, numbering more than 100 billion bacterial cells per cubic inch, living in the clay-filled cracks. This density of bacteria is similar to that found in the human gut. That compares to a paltry 1000 bacteria per cubic inch living in the muddy layers above the rock on the ocean floor.

"I thought it was a dream, seeing such rich microbial life in rocks," said Associate Professor Yohey Suzuki from the University of Tokyo, one of the leaders of the expedition. "Honestly, it was a very unexpected discovery. I was very lucky because I almost gave up."

This finding excites astrobiologists who search for signs of past, or present, life on Mars. Much of Mars was once covered by lakes and oceans, with similar clay minerals. Just as in the Earth study, Martian ocean sediments were eventually covered and compressed into rock at the bottom of those bodies of water.

"Minerals are like a fingerprint for what conditions were present when the clay formed. Neutral to slightly alkaline levels, low temperature, moderate salinity, iron-rich environment, basalt rock -- all of these conditions are shared between the deep ocean and the surface of Mars," said Suzuki.

Mars 2020 Rover Perseverance. Credit NASA

NASA will launch the next Martian rover, Perseverance, in late July or early August. Among other scientific instruments, Perseverance posses a biological testing lab that will search for similar bacterial colonies, living or fossilized, in similar Martian rock that was once the bottom of a Martian sea. The findings of Dr. Suzuki’s team gave NASA scientists the road map for searching for ancient, Martian bacterial colonies that may, perhaps, tell us that Mars was once, possibly still is, a home for life.

 Each month, I write an astronomy-related column piece for the Oklahoman newspaper. On the following day, I post that same column to my blog page.

This is reprinted by permission from the Oklahoman and www.newsok.com.

Human-Tardigrade Hybrids May Be the First Earthlings to Visit Mars

Tardigrades, also known as water bears for their cute appearance, are amazingly hearty microscopic creatures. They can survive being frozen, thrown in boiling water, and other extreme conditions that destroy almost all other Earthly lifeforms. In an experiment by the European Space Agency, a batch of tardigrades sat outside of a satellite in the freezing cold vacuum of space for ten days while intense UV and cosmic radiation bombarded them constantly. Most survived.

Earlier this year, an Israeli lunar lander carried thousands of tardigrades on board as a test to see if they are capable of surviving the harsh conditions of the lunar surface. The craft crashed, but these little guys are so tough, scientists believe that many likely survived that crash.

Tardigrade, also known as a water bear. Credit Shuttercock

Intense radiation remains a major hazard when traveling in space beyond Earth orbit. To go to Mars, for example, astronauts need lots of shielding from cosmic rays, which means lots of weight. And that means a huge launch cost. Astronauts less affected by space radiation can survive with less shielding. And since Mars does not possess an ozone layer to protect against UV radiation or a strong magnetic field to protect against cosmic radiation, life becomes very dangerous for astronauts or colonists there.

NASA plans on sending astronauts to Mars within 15 years. Private companies plan on sending colonists there sooner, perhaps by 2025. We have the technology to get humans to Mars within the next 5-10 years. We may well make the discovery of all time by finding native life there. But can we keep our human Martians safe?

Water bears may hold the answer. Or at least their genes. Scientists studying tardigrades have discovered many of their genetic secrets of survival, and now some have suggested that incorporating tardigrade genes into humans may make it possible for us to survive more easily on Mars or even alien planets.

Would you be willing to become a human-tardigrade hybrid to be the first human on Mars?

Each month, I write an astronomy-related column piece for the Oklahoman newspaper. On the following day, I post that same column to my blog page.

This is reprinted by permission from the Oklahoman and www.newsok.com

Did NASA Already Find Martian Life?

In 1992, astronomers discovered three objects roughly the size of Earth orbiting another star, the first known exoplanets. No one expected life on those objects because the star was a pulsar, the remains of a star that blew up as a supernova, and the “planets” had actually formed from the debris of that explosion.

Three years later, astronomers found the first true exoplanets orbiting the sun-like star 51 Pegasi. Now, the NASA Exoplanet Archive lists 4113 confirmed exoplanets with more than 3600 exoplanet candidates awaiting confirmation. Astronomers believe that we have only touched the tip of the exoplanet iceberg. Data suggests that our Milky Way galaxy alone contains some two hundred billion planets. As of now, there’s no solid evidence suggesting that life exists on any of them.

But some scientists believe that we already found life on another planet, one much closer to home. In 1976, NASA landed twin spacecraft on Mars, Viking 1 and 2. Each included automated laboratories designed to search for microscopic life on the Red Planet.

Both craft, which landed 4000 miles apart, included a simple test called the Labeled Release experiment. It added a nutrient broth to a small amount of Martian soil and checked to see if any metabolic byproducts, like carbon dioxide, were released. Every test by both landers reported positive results. However, the other experiments on both landers found no organic chemicals, which seemed to preclude any lifeforms. Since then, most scientists decided that some odd chemistry in the Martian soil falsely mimicked those life signs.

Viking Lander, credit NASA

But not all scientists. Gilbert Levin was the principal investigator for the Labeled Release experiment for both landers. In a recent article in Scientific American, he wrote “The Viking LR (experiment) sought to detect and monitor ongoing metabolism, a very simple and fail-proof indicator of living microorganisms. Several thousand runs were made, both before and after Viking, with terrestrial soils and microbial cultures, both in the laboratory and in extreme natural environments. No false positive or false negative result was ever obtained. This strongly supports the reliability of the LR Mars data.”

It may be decades or centuries before we confirm life on an exoplanet, if we ever do. But we may have already discovered life on another planet, right next door.