Audio guide transcript for Space: Could Life Exist Beyond Earth?

Finding life beyond our planet could change everything. It would alter our understanding of existence. More than ever before, scientists believe that extraterrestrial life may exist. Unrestricted by the limitations of the human body, robots are searching distant worlds, and colossal telescopes are detecting never-before-seen planets. Hidden deep in oceans or buried underground, simple lifeforms may be thriving within our Solar System. Beyond that, in the infinite reaches of our universe, the possibilities are endless.

In this room, a giant sphere is suspended and shows a gently moving constellation of dots on a black background. As the dots grow larger it becomes clear that they are different types of microbes, moving around and growing in scale and density on the sphere, before reducing down in size once again.

Tiny single-celled organisms, or microbes, like these were the first living things on early Earth, and they thrived in its harsh conditions. Today, some microbes still survive in Earth’s extreme environments. They help scientists decide where to look for life on other worlds, and predict what that life might be like.

When life began on Earth, it was a very different planet to the one we know today. A dimmer sun shone through a hazy sky, air that would be toxic to most life today. Volcanic eruptions ripped through a surface dominated by oceans. Understanding how life emerged on this volatile and inhospitable world helps us predict where and how life could arise beyond our planet. Earth’s surface is constantly changing, as it has been over the 4.5 billion years of its existence. Finding evidence of Earth’s beginnings and early life is difficult. But there are clues to be found.

These wavy, colourful shapes were made by microbes approximately 3.5 billion years ago. The microbes, growing in layers one on top of the other, lived in a lagoon – a shallow body of water by the sea. These traces are the closest we can get to the beginnings of life on Earth.

Meteorites are some of the only physical clues to how our Solar System formed and what else is out there. When collisions happen between planets, moons or asteroids, fragments can break off. If a piece lands on the surface of Earth, it’s called a meteorite. All the meteorites on Earth come from our closest neighbours – asteroids, the Moon and Mars.

A Slice of Space

Touch this slice of metal meteorite. This one is a small part of a much larger 24-tonne meteorite, known as the Mundrabilla meteorite.

Millions of asteroids hurtle through our Solar System. Their spinning surfaces switch rapidly from boiling hot to freezing cold as they turn to and from the sun. These environments are too harsh and unstable for life to exist, but they could play a key role in the origins of life elsewhere. Recent space missions have ventured to asteroids, hoovered up tiny samples and returned them to Earth. These precious grains have revealed something extraordinary: they contain the elements essential for life to begin. In our chaotic early Solar System, asteroids likely delivered these ingredients to Earth. Could they have delivered them to other worlds as well?

Spacecraft: Hayabusa2
Space agency: Japan Aerospace Exploration Agency
Launch: 2014
Samples delivered to Earth: 2020

All meteorites are immediately contaminated when they enter Earth’s atmosphere, and again when they land on Earth’s surface. In 2020, the Hayabusa2 mission obtained uncontaminated samples from the asteroid Ryugu, returning around five precious grammes to Earth. The samples revealed that the asteroid contains some of the key ingredients for life to start, including carbon, nitrogen, hydrogen, oxygen, and water trapped within minerals.

Asteroid Ryugu Discoveries

This rock fragment is from asteroid Ryugu. Despite being tiny, it reveals new information about our Solar System. Scientists, including some here at the Natural History Museum, have found that Ryugu contains high amounts of carbon, as well as traces of water trapped inside minerals.

Spacecraft: OSIRIS-REx
Space agency: NASA
Launch: 2016
Samples delivered to Earth: 2023

Asteroid Bennu was chosen because it was close to Earth, and there was a chance it contained water and elements essential for life. It took seven years for the OSIRIS-REx spacecraft to reach Bennu, collect the sample and return. Scientists at the Natural History Museum have helped discover minerals in Bennu related to life’s origins, some never seen before in space rock samples.

Gathering samples from a crumbly asteroid

The OSIRIS-REx mission team had a huge shock when the spacecraft touched down on asteroid Bennu. Its surface was not solid as they had predicted, but more like a pile of rubble that the spacecraft sank into.

Once landed, the spacecraft’s sample head – the part that collects the sample – kicked up pieces of the surface by releasing a puff of nitrogen gas. The sample head could then gather these dislodged fragments of asteroid, placing them safely in a container. The capsule was so full that some rocks spilled out into space before the lid could fully close.

Mars is a desolate place, a cold, dry desert constantly bombarded by radiation from space. But Mars wasn’t always this way. Ancient Mars was warm, wet and protected by a thick atmosphere, and simple life could have thrived on the surface. Today, any life would have to be hidden deep underground. Robotic rovers are discovering evidence of this past watery world and searching for signs of ancient life. If traces of life are found on Mars, it would be the first evidence that life on Earth is not unique.

Rover: Mars 2020 Perseverance
Space agency: NASA
Launch: 2020
Arrival: 2021

Some places on Mars, like the Jezero crater, were once covered by lakes of water that provided ideal conditions for life to thrive. The Perseverance rover is searching for traces of ancient microbial life by sampling and analysing Martian rocks from the Jezero crater and surrounding areas. The rover has already found evidence of past water and carbon, along with other key elements related to the building blocks of life, but no direct evidence of life itself.

Venture onto the surface of Mars and experience a day of dust storms, whirlwinds and shifting light. Glimpse into the past when Mars was much more like Earth, and rivers and lakes were features of the landscape. This experience was created based on data, sounds and images collected by the Mars 2020 Perseverance rover in Mars’s Jezero crater.

This large projection on a curved screen displays an animated Martian landscape over a day and night cycle. From a dark sky, the Sun rises behind a Martian landscape edged by mountains. The Sun appears smaller than it does from Earth and the sky has an orange tint compared to Earth’s sky. In the daylight, the Ingenuity Mars helicopter flies into the crater alongside the Perseverance rover, as a whirlwind of dust swirls towards you and dissipates into the air. A hand symbol appears on the screen, offering you the opportunity to open a window back in time around 3.7 billion years, when the crater was full of water. The windows disappear and back on present Mars a dust storm is picking up, engulfing you in a fine orange fog. As the storm passes, shadows grow longer and day transitions to night. Stars move across the sky and the glow of a meteor passes overhead. Hand symbols once again appear on screen, opening windows to glowing lava flows that existed here around 4.1 billion years ago. The windows close and a blue star – Earth – is visible in the dark sky. The cycle of night to day begins again.

This image shows scientists announcing their findings about Martian meteorite ALH84001 at a press conference in 1996. They had discovered structures and minerals inside, which they suggested were produced by ancient Martian microbes. US President Bill Clinton even made a televised announcement about it. Scientific debate and further research demonstrated that it wasn’t evidence of life after all, driving the new scientific field of astrobiology.

Rover: ExoMars Rosalind Franklin
Space agency: European Space Agency
Planned launch: 2028
Planned arrival: 2030

Since 2016, an orbiting spacecraft has been studying Mars in the first phase of the ExoMars mission. The next phase is nearly ready and involves this rover exploring a new area of the planet. Venturing further beneath the dusty red surface than any previous mission, it will seek signs of ancient water and past or even present traces of life.

Once the Rosalind Franklin rover lands on Mars, it will explore up to two metres below the Martian surface. With only a small number of chances to drill, it will investigate only the most promising sites. The rover instruments will study the rocks and analyse samples in its onboard laboratory.

Hundreds of millions of miles away, mysterious moons orbit Saturn and Jupiter. Tantalising evidence of liquid water has been detected, hidden deep beneath their cracked icy crusts. As scientists discover more about life at the depths of Earth’s oceans, the possibility of life thriving in similar conditions on these icy worlds expands. New space missions are about to give us an unprecedented view of these distant places and look for the same essential elements that make life possible on Earth. While life on Mars is most likely extinct, life could exist today in these hidden oceans on the moons of Saturn and Jupiter. If found, life on these worlds could be our closest living neighbours.

Spacecraft: Juice
Space agency: European Space Agency
Launch: 2023
Planned arrival at Jupiter: 2031

A new mission is set to find out if life could thrive in the hidden oceans of our Solar System’s icy moons. The European Space Agency’s spacecraft Juice is on its way to three of Jupiter’s moons – Ganymede, Callisto and Europa. Orbiting the moons, Juice will investigate what’s beneath their frozen surfaces, measuring the thickness of the ice and mapping hidden oceans.

Exploring the outer Solar System

Hanging in this zone of the exhibition is a 1:10 scale model of the Juice spacecraft. Juice’s outstretched wings are solar panels – the largest ever built for an interplanetary journey. On board the spacecraft, ten research instruments work together to study Jupiter and the oceans beneath the crust of its icy moons.

Hydrothermal vents erupt hot fluid from the seafloor and are home to thriving communities of life in the depths of Earth’s oceans. The discovery that life exists in these seemingly inhospitable environments challenged our understanding of life’s limits. While most familiar ecosystems use sunlight as a source of energy, hydrothermal vents use Earth’s own heat and chemical nutrients. Microbes that thrive on this energy are the foundation of these underwater ecosystems. The creatures in these deep, dark ocean communities can provide insight into how life could adapt to conditions under icy crusts on distant moons.

Pillars of the deep-sea oasis

In a world without sunlight, towering structures rise from the ocean floor, spewing hot, mineral-rich water. The fragments on display come from one of these structures – a hydrothermal vent chimney and hood. Alongside these vent fragments, specimens of creatures that live around the vents are on display. These include a scaly-foot snail that has iron in its shell and foot to protect it from the harsh conditions near vents, shrimps that use special organs on their backs to detect extremely faint light emitted by hydrothermal vents, and the Pompeii worm which is the most heat-tolerant animal known on Earth, living in up to 80°C waters around hydrothermal vents.

The search for life doesn’t stop at the edge of our Solar System. Until recently we could only presume that planets orbited the stars in the night sky, but today, advanced telescopes are enabling us to discover and study a multitude of solar systems. Undiscovered territories are emerging – ocean worlds, volcanic planets, and planets that orbit more than one star. Somewhere in this vastness, life more complex than simple microbes could exist. With technologies advancing and potentially billions of planets out there, are we on the cusp of making one of the most profound discoveries in human history?

Spacecraft: James Webb Space Telescope (JWST)
Space agency: NASA
Launch: 2021
In operation from: 2022

On Earth and in space, giant telescopes scan the cosmos, discovering planets orbiting distant stars. By analysing their atmospheres, scientists are trying to understand which planets are habitable and are searching for signs of life. The JWST is currently the most powerful eye on the cosmos, but newer, more powerful telescopes are in the making.

A window to other worlds: JWST replica mirror

The JWST is made of 18 gold-plated hexagonal mirrors and works by capturing the faintest light from distant planets. By analysing this light, scientists can identify the chemical make-up of the planets’ atmospheres, searching for signs of water and gases such as methane. The mirror on display is a full-size replica of a single mirror, as the originals are made of beryllium, a substance toxic to humans.

We don’t know what life beyond our Solar System might be like, but astrobiologists can make an educated guess based on what we know about life on Earth. Different and unrelated types of life on our planet have evolved similar features to respond to the same challenges, developing traits such as fins to swim and wings to fly. Using evolutionary science as a foundation, astrobiologists have speculated about the types of adaptations likely to evolve on certain exoplanets based on their particular conditions. Meet some of their imagined life forms.

The final space of the exhibition is dark, with discs of different sizes suspended at different heights. Projected, animated imagery of nebulae drift across the discs. Four spotlights on the floor encourage visitors to approach certain discs, activating animations of imagined life forms.

The first life forms are plants with hollow cups on the top of stems protruding from the ground. They sway in the wind. A small glowing dot travels towards the open cup of the lowest plant. The cup closes around the dot, devouring it.

The second and third life forms are situated in underwater environments. A pink, shrimp-like creature with one eye propels itself in bursts through the water, sunlight streaming onto it from above. Below, a crab-like creature with no eyes and an extremely smooth shell sits on the dark seafloor.

At the final stop, a transparent tube undulates across the screen, a colony of microbes floating through clouds.

Intermittently, all of the discs in this space display one single, drifting image of a nebula.