You know I love writing about alien worlds and the possibility of alien life. I also love science fiction books and movies. These are mutually inclusive most of the time, which brings me to the topic of the day – water worlds. Do you remember the 1995 Kevin Costner movie Waterworld? This movie re-imagines the Earth as an almost entirely “water world” (the Earth is already its 70 percent ocean) after the melting of the polar ice caps due to climate change. All the continents have submerged and only a few islands remain. Only a few humans including Costner’s character “Mariner” have survived in this post-apocalyptic world.
Fast forward to 2014 and another very different movie called Interstellar, by the renowned director Christopher Nolan. In Earth’s future, a global crop blight and second Dust Bowl are slowly rendering the planet uninhabitable. Prof Brand (Michael Caine), a brilliant NASA physicist, is working on plans to save mankind by transporting Earth’s population to a new home via a wormhole.
But first, Brand must send former NASA pilot Cooper (Matthew McConaughey) and a team of researchers through the wormhole and across the galaxy to find out which of three planets could be mankind’s new home.
They first land on a planet called Miller’s Planet, which is a world covered almost entirely with a water-like substance. All appear calm on the “surface” of the planet until a massive 1.2 km high wave appears over the horizon. There are many other water worlds in science fiction movies and novels.
This is in the realm of science fiction, but now we move over to science fact. Scientists now say that “water worlds,” or Exoplanets (planets outside our Solar System) that contain lots of water, are actually very common.
A team of experts has been digging into data obtained by the Kepler space telescope, as recently revealed at a conference in Berlin. Kepler has discovered more than 4,000 Exoplanets so far, some of which could support alien life. Around 35 percent of the planets (around 1,400) that are bigger than Earth are “likely” to have water. Even more excitingly, some are believed to have as much as 50 percent water - far more than Earth’s 0.02 percent water-weight.
Interestingly, all planets studied ended up being 1.5 times to 2.5 times the size of Earth. It turns out that planets 1.5 times the size of the Earth are very likely to be rocky, and 2.5 times our size, water worlds. Even in our own solar system, Mars and several moons of other planets are believed to be having water.
What is the significance of discovering water worlds ? Life on this planet evolved because of and remains due to the availability of water. Water is very important in the search for aliens for the same reason – water is an essential component of life.
Note that there could be life forms out there which do not need water – in another nod to science fiction, the aliens in M. Night Shyamalan’s hit movie “Signs” (2002) are allergic to water. Moreover, organisms have been observed on the sea floor that have very different organic requirements.
Although this dark, oxygen-poor environment might seem like a harsh place for life, organisms from bacterial colonies to thermophilic worms to heat-tolerant crustaceans can thrive by undersea volcanic vents, something scientists once thought was impossible.
But it is generally agreed that where there is water, life could not be far behind. Water’s strong hydrogen bonds encourage compounds to come together and it can transport electrons - which is important for producing energy.
However, the search for water in space is difficult because examining the composition of planets isn’t easy given their distance from Earth. Using information from NASA’s Kepler and the European Space Agency’s Gaia satellite, scientists were able to make predictions about the composition of Exoplanets.
Do not wait for a dip in these waters yet - their surface temperature is expected to be in the 200- to 500-degree Celsius range. Their surface may be shrouded in a water vapor-dominated atmosphere, with a liquid layer underneath.
“Life could develop in certain near-surface layers on these water worlds when the pressure, temperature and chemical conditions are appropriate,” a researcher told the media. As Geoff Goldblum’s character Dr. Ian Malcolm says in Jurassic Park (1993), “Life finds a way”.
The search for more Exoplanets will get a boost with the recent launch of NASA’s new TESS satellite (Transiting Exoplanet Survey Satellites). TESS, which launched in April, will survey 200,000 of the brightest stars to find transiting planets, some of which may have water.
These efforts will get another boost by 2021, when the James Webb Space Telescope is launched. And NASA and other space agencies have hopes of sensing robotic probes to the water worlds in our solar system and beyond.
In preparation, NASA was set to send a submarine to the seafloor near Hawaii in an effort to find an environment analogous to water worlds like Jupiter’s moon Europa and Saturn’s moon Enceladus, foreign news media reported last week. The NASA submarine SUBSEA, (Systematic Underwater Biogeochemical Science and Exploration Analog will reach the volcanic vent Loihi -- a seamount off the coast of the Big Island of Hawaii.
At Loihi, the submarine it will take observations at sub-centimeter resolution of the topography, environment, and inorganic chemistry. Taking a closer look at the Earth’s seafloor might help the space agency to send a submarine to the outer solar system to explore the waters of other worlds for life.
Water worlds could be teeming with life. Exploring the oceans in other worlds would be a tall order, as we have not explored almost 90 percent of our own ocean.
As someone said, we know more about the far side of the moon than we know about the ocean. Scientists have only identified 228,450 marine organisms and at least five million more species are believed to be living in the dark depths of the oceans, some in fairly inhospitable conditions. It will take years, if not decades, to learn more about them and classify them scientifically.
In any case this is a major breakthrough in our efforts to learn more about planets outside the solar system and the possibility of alien life.
The fact that other worlds bearing water may be more common than previously thought will be a boon for the search for Earth 2.0 – a planet mostly similar to Earth that we can inhabit one day.
The Earth does have an expiry date, which Mankind may inadvertently bring forward due to climate change. It is better to have another place to relocate to in our cosmic neighbourhood when that happens.