My Science School

Technological advancements have virtually brought Mars closer to us step-by-step, first as blurry images through telescopes, then as data collected remotely by flybys and orbiters, and finally as physical observations conducted by landers and rovers that can test the Martian air and terrain for us. Today we are even planning sample return missions, and one day in the near future we will also have our first human on Mars!

But carrying out a mission to Mars is no easy job. Based on the scientific intent of the mission, items of equipment for the spacecraft have to be designed, built, tested and optimized. Since Mars is far away from the Sun, solar energy available on the planet will be limited, and efficient systems will have to be designed to power our equipment. A rocket, best suited to carry its payload, also has to be selected.

Mars is millions of kilometres away from the Earth. The differences between their orbits and orbital speeds mean that the two planets are the closest only for a limited duration. So, to execute the fastest and most efficient mission, we will have to time our rocket to Mars perfectly within a specific period known as the “launch window” which comes only once every two years and two months! Also, it usually takes around six to nine months for a spacecraft to reach Mars! So we have to plan our mission well in advance. And all this must be done keeping in mind the cost of the mission!

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Robert A. Heinlein (1907 - 1988) was an American naval officer and aeronautical engineer who made a name as a science fiction writer! His works were scientifically accurate and logical to a degree that had never been seen before in science fiction. And thus, a new subcategory of the genre was born - hard science fiction - and it had a lasting influence on the generations of readers and writers of fiction that followed Heinlein!

Among the many novels Heinlein wrote for young adults aged between 12 and 18 is Red Planet, a gripping tale of adventure set in Mars, published in 1949. Years later, it was adapted by Fox Kids and made into a three-episode animated mini-series.

The novel tells the story of two friends, Jim and Frank, who live in a boarding school on Mars, along with Jim’s Martian pet, Willis the Bouncer. One day Willis overhears conversations between the greedy principal of their school, and the corrupt administrator of their Martian colony about a plan which threatens to put all Martian colonists in immediate danger. When the boys get to know about this evil plot, it is up to them to save everyone’s lives!

This book contains a lot of detail about Mars and its terrain. It also features the Martian canals popularized by the American astronomer, Percival Lowell!

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Imagine writing a full novel without realizing that you wrote one! That was what happened to Ray Bradbury, the author of The Martian Chronicles! Though this book is a collection of (fictional) events set in chronological order (which is why it is called chronicles), Bradbury had written them all for different publications at different times. He realized only later that all those stories sharing the same fictional timeline on Mars could be put together to make a single novel! And that was how The Martian Chronicles came to be published in 1950.

The book has three parts. In the first, the Americans send exploratory missions to Mars. Though the Martians try to fight off the invaders, they fall prey to a human-introduced chicken pox epidemic that nearly wipes them off the face of the planet. In the second part, the Americans successfully colonize the Red Planet. But peace on the Earth breaks down, and with a war fast approaching, most human settlers on Mars leave for the Earth. The third part of the book shows the aftermath of the nuclear war that destroys the Earth. The few humans who remain on Mars are all that is left of our race.

The strong influence of the two World Wars can be seen in this novel. Bradbury writes, “We earth men have a talent for ruining big, beautiful things.” How true!

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Back in 1877, while Schiaparelli was busy making scientific notes on the surface of Mars, never in his dreams would he have imagined the lasting impact his Martian canali would have on the genre of science fiction!

Just three years after his (mistaken) discovery, a science fiction novel, called Across the Zodiac, was published in which an explorer goes to Mars, and meets Martians who refuse to believe that he is from the Earth. This book, written by Percy Greg, is also said to contain the first use of alien language in fiction! Another popular novel, Journey to Mars (1893), written by Gustavus Pope, is about humans who get kidnapped by Martians.

Meanwhile, the American astronomer Percival Lowell, under the belief that Mars was home to intelligent beings who were constructing waterways to revive their dying planet, popularized his views through three books starting with Mars (1895). Though his publications were not intended as fiction, countless writers of science fiction took inspiration from his descriptions, and their works went on to become bestsellers! Kurd Lasswitz’s Auf zwei Planeten (1897) translated as Two Planets (1971), H. G. Wells’ The War of the Worlds (1898), Edgar Rice Burroughs’ A Princess of Mars (1917) and its sequel The Gods of Mars (1918), Robert A. Heinlein’s Red Planet (1949), and Ray Bradbury’s The Martian Chronicles (1950) are among them.

Auf Zwei Planeten, meaning “On Two Planets” in German, was a popular science-fiction novel about intelligent Martians and how they change life on the Earth. Its author, Kurd Lasswitz (1848 - 1910), a German writer, educator and philosopher, was called “the father of German science fiction.” Though originally published in German in 1897, more than seven decades passed before the book was translated to English! The book, Two Planets, published in 1971 was based on an abridged version of the original novel.

In Lasswitz’s book, a group of explorers come across human-like Martians (but with much larger eyes) of superior intelligence who have set up camp on the Earth’s North and South poles. They are an ancient race, technologically far more advanced than humans - they use anti-gravity devices and rapid transport systems, eat synthetic food and have canals and space stations - but they are running out of water. They try to give humankind education and technologies in exchange for air and solar power which will help them revive their planet. But conflict arises and the Earth becomes a Martian colony! What happens afterwards forms the rest of the novel.

With its accurate descriptions of space travel and portrayal of a highly advanced society built on scientific principles, the novel was very popular in Germany, especially among youngsters. Science writer, Willy Ley, and aerospace engineer, Wernher von Braun, both famous German-born Americans, are said to have been inspired by Lasswitz’s writings.

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Fifty-six years have passed since the first successful flyby of our red planetary neighbour. As we continue to plan and send more spacecraft to Mars, each more advanced than the previous one, what do we hope to achieve?

Proving (or disproving) life on Mars is perhaps the foremost thought in the mind of every scientist. Did life ever exist on the Red Planet? Can it sustain life today? To answer these questions we need to look for things that make place habitable - liquid water and a source of energy-and biosignatures, evidence of past or current life.

We also hope to learn more about the Martian climate. Today we know about the infamous Martian dust storms, and the seasonal deposits of carbon dioxide frost on the ice caps. But we don’t fully understand the processes that drive them. We don’t know for sure whether Mars was once a warmer and wetter planet, and if so, about the factors that brought about this drastic change.

Collecting more data on the planet’s geology - its structure and composition, the history of its evolution, and the processes that act on it - will also help us understand why Mars is how it is today. Upcoming Mars programmes, including rovers, orbiters and the proposed Mars sample return missions, will also prepare us for human exploratory missions in the not-so-distant future!

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From the time we first learnt to spot this bright reddish orb in the night skies, Mars has held a special place in our minds. Many ancients named it after their gods of war. Mars as the Roman god of war featured in mythological stories, and Ares (the Greek god of war) is a main character in Homer’s epic poem Iliad, thought to be written in the 8th century BCE.

Works of fiction in more modern times were more concerned with the actual planet itself. Even though many stories were written in the 1800s about voyages to the Red Planet, Mars became a preferred subject of science fiction probably after the Italian astronomer Giovanni Schiaparelli (mistakenly) identified “canali” on Mars in 1877!

When the prominent American astronomer Percival Lowell announced that he had found Martian irrigation canals, and wrote books about life on the planet, he further popularized the idea of Mars being home to intelligent beings.

Many books written in these times were about alien invasions, Martian-Earthling hostilities, and sometimes about a sympathetic, highly advanced race of Martians.  This trend continued long after Lowell’s canal theory was proven false.

Later, after the Mariner and Viking missions showed Mars to be a dry and barren planet, the subject of Mars-based stories and novels shifted to the efforts made by humans to shape the planet for habitation.

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Consider this. While on a mission to find life on Mars what if we accidentally introduce life to the planet instead?

It may seem unbelievable at first - the robotic spacecraft that we send today have to travel millions of kilometres through space to reach Mars. On the way it faces vacuum, extremely low temperatures, high levels of cosmic radiation and what not! Which life form, if it hitches a ride on the spacecraft, can survive all that? But as it turns out, some microorganisms can withstand it all, and tiny life forms called extremophiles (from extremus, meaning “extreme” in Latin, and philia, meaning “love” in Greek) are an example of that! In effect, the risk of “forward contamination,” or transfer of life and other biological contaminants from the Earth to another celestial object, is very real. This raises two concerns.

One, such hitch-hiking microorganisms may be mistaken for signs of extra-terrestrial life. Two, they may thrive and go out of control in the new environment, and even interfere with or destroy any life forms that may originally exist there.

Today, spacecraft to Mars are thoroughly sterilized to prevent such accidents. But in the future when we, humans, become equipped to go on Martian missions, this will become one more issue to solve. Because our bodies are natural hosts to trillions of microbes, some of which help us survive, and a few of them are bound to spill over!

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As on date, scientists have identified around 300 meteorites from Mars, and some of them (through their chemical composition) have shown proof of water on the planet. Still fewer seem to carry something extra - signatures of Martian life! Or do they? Nearly four decades have passed since the most significant one among such meteorites was found, and scientists haven’t reached a consensus yet!

The Martian meteorite Allan Hills 84001 (ALH84001) was found on Alan Hills, Antarctica, in 1984. Though this four-billion-year-old meteorite landed on the Earth only around 13,000 years ago, ALH84001 was ejected from Mars by an impact event about 17 million years back! Chemical analysis showed that it was exposed to water on Mars.

But it was in 1996 that ALH84001 burst into public consciousness - when a team of scientists announced that they had found fossils of tiny bacteria-like life forms, called nanobacteria, in it! But this finding was (and still is) hotly debated.

Many argue that the so-called fossils aren’t fossils at all but simply organic material (compounds of carbon and hydrogen, which may also contain oxygen, nitrogen and other elements) that can form without the involvement of living matter, and that nanobacteria itself exists only in theory, not in real life.

Another Martian meteorite that landed in Egypt in 1911, called the Nakhla meteorite, also had carbon-rich structures inside which could be the products of bacteria. But this too is considered insufficient evidence for life on Mars for similar reasons.

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We haven’t found the evil master plans of little green men of Mars plotting to invade the Earth. Or the canal layout designed by Martian engineers! But that doesn’t necessarily mean that Mars has no life. Because today when we search the Red Planet for signs of life, we are looking for something more basic - like chemicals that point to the presence of microorganisms!

Biosignatures, or substances that indicate the presence of (past or present) life, can be found either on the Martian surface, or underground, in its soil and rock, or in its atmosphere as gases. So do we screen the entire planet for life? No! Instead, scientists have found a shortcut - they look in places that may have been (or still are) habitable, starting with areas that show evidence of liquid water.

Gale, a crater on Mars that may have contained a lake billions of years ago, is one such location. The U.S. National Aeronautics and Space Administration’s (NASA) Curiosity rover has detected proof of ancient water and organic chemicals in the crater. The level of methane, a gas that can be associated with the presence of microorganisms, was also found to vary with the seasons in the Martian atmosphere. Though they are not a guarantee of finding life - because organic materials can be produced through non-biological processes also - they still are promising signs of a microbe-friendly habitat!

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While looking up at the night sky and all the stars and planets in the vast expanse of space around us, have you ever wondered whether life exists outside this little Blue Planet we call our home? How life started here in the first place, and what the future looks like for us humans? We can say that Mars is our stepping stone to finding the answers to these questions!

Of all the planets in our solar system, Mars is perhaps the closest the Earth has in terms of surface conditions. Scientists say that Mars once used to have a thicker atmosphere, and even a warmer, wetter climate. But something happened that caused a huge change in its climate, and we would like to know why. Learning more about Mars will tell us something newer about the Earth’s past - how the planet was shaped, and maybe even how life evolved on the Earth.

This brings us to the question that concerns our future. Can another planet sustain life? Our first clue to answering it lies in understanding the history of water on Mars, because life as we know it needs water. Even though the Mars we see today appears dry, barren and cold, we have also found evidence of water on it. Through further explorations and studies we hope to discover more about this strange Red Planet, and through it, about ourselves too!

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Looking at the photographs of the dry and dusty Mars, would you believe that billions of years ago the planet had enough water to cover about one-fifth of its surface? Scientists say that the Red Planet once used to have rivers, lakes and vast oceans as well! Back then, Mars may have had a thicker atmosphere which made it a warmer and wetter planet than it is today.

Evidence of Mars’ “watery” past can be found on its surface itself. Certain minerals found in Martian rocks could have formed only in places where water was present. The Martian outflow channels and valley networks point to a time when liquid water used to flood or flow across the Martian surface. Lake beds with tell-tale delta formations have also been reported. Even Martian meteorites found on the Earth show that they were exposed to water on their parent planet!

Today, the thin atmosphere of Mars would cause any liquid water on the surface to evaporate. But still water exists in the frozen form as polar ice caps, and potentially beneath the Martian surface. Scientists have also found dark streaks on steep slopes, called Recurring Slope Lineae, or RSL, that were believed to be a mixture of soil and highly concentrated salt water flowing down the Martian slopes. (But some scientists argue that they may just be streams of sand and dust.)

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On photographs gullies look like little wrinkles on the surface of Mars. But they are actually channels that run for hundreds of metres!

Called gullies, because of their similarity with the gullies seen on the Earth, they are found on both the northern and southern hemispheres of Mars, but are more common on the southern side. They are seen on steep slopes, like those inside craters, mostly on the sides that face the nearest pole. Looking at the near absence of craters in gullies, scientists say they may be very young formations!

Gullies usually have an hourglass shape - starting with “alcoves” (branched, root-like formations made up of smaller grooves) at the top of the slope that merge into a single channel, and ending in a fan-shaped deposit of debris called “apron” at the bottom. Smaller forms of gullies, called linear dune gullies, are found on the slopes of Martian sand dunes.

Though the grooves they cut are long, their alcoves are very small, and they may not even have aprons. Instead, they have raised banks known as levees on either side of their channels.

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When scientists first discovered gullies on Mars, the news generated a lot of excitement. Similar features on the Earth are created by flowing water, and so Martian gullies seemed to indicate the presence of liquid water on the planet!

Initially, all evidence seemed to point to just that - water that might have come from the melting of glaciers or snow packs during summers, from underground stores of water (called aquifers), or from the thawing of ice trapped in the frozen Martian ground. This liquid water might have eroded the ground as it flowed down the slopes, carving out the gullies we see today, and deposited debris, collected along the way, in the gully aprons at the bottom of the slope.

Later on, scientists studying the images of linear dune gullies taken by the U.S. National Aeronautics and Space Administration’s (NASA) Mars Reconnaissance Orbiter noticed something peculiar - the gullies seemed to form during spring-time. This could have been because they were carved by chunks of dry ice, not water! Scientists say that during Martian winters, a layer of carbon dioxide frost forms over the upper reaches of the gullies. With the arrival of spring, blocks break off from this sheet of dry ice, slide down the dune slopes and create the grooves we call linear dune gullies!

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A branching network of grooves that look like the river drainage basins on the Earth — who would have thought we would see them on Mars? These are the valley networks, found mainly in the southern highlands region of Mars.

Martian valley networks are typically made up of narrow channels that are a couple of hundred kilometres long, one to five kilometres wide, and 50 to 200 metres deep, even though some may be longer. Like that of a river on the Earth, their cross sections are initially V-shaped, and gradually change to a U-shaped or flat-bottomed form towards the lower ends of the channel. Some of them also seem to carry evidence of flowing water.

The networks are made up of small channels that merge into bigger tributaries over and over until they join to form a single stream. This gives a valley network the appearance of the roots of a tree!

Scientists used to say that the Martian valley networks may have formed billions of years ago when liquid water used to flow across the Martian surface. But some argued that they may also be the products of tectonic activity, or other types of erosion, such as by wind, glaciers, or lava.

Most recent reports support the theory that they were carved by water seeping under glaciers that once used to cover the southern highlands!

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