NASA is plotting a new mission that could be the one to finally uncover alien life in the universe.
Or, it may uncover a darker fact: that we humans are completely alone, on the unique oasis we call Earth.
Planet K2-18b, which astronomers believe has water in its atmosphere, orbits within the habitable zone of a distant star[/caption]
Scientists will be looking for signs of oxygen, ozone and methane in a planet’s atmosphere, as these are the chemicals that suggest there might be life on the surface[/caption]
The ambitious project, slated to arrive sometime in the 2040s, will require technologies that are yet to be developed and demonstrated.
Fortunately, plans for those technologies are underway as part of an international effort.
The Habitable Worlds Observatory (HWO) will be tasked with scouting out some of the nearly 6,000 exoplanets that have been discovered since the early 1990s.
“If we’re going to find evidence of alien life beyond our solar system in our lifetime, the Habitable Worlds Observatory represents our best opportunity,” Dr Caroline Harper, head of space science at the UK Space Agency, told The Sun.
“This groundbreaking mission could finally answer one of humanity’s most profound questions: are we alone in the universe?”
Dr Shyam Balaji, a theoretical physicist at King’s College London, said that finding a planet with a stable atmosphere and potential signs of life would be “a turning point”.
“It would reshape how we see our place in the cosmos, and even short of detecting life,” he said. “Simply confirming that other habitable worlds exist would profoundly change our understanding of the universe and of our own planet’s uniqueness.”
The HWO will look for chemical patterns – what scientists call biosignatures – around Earth-sized planets that lie within the habitable zones of nearby stars.
Scientists will be looking for signs of oxygen, ozone and methane in a planet’s atmosphere, as these are the chemicals that suggest there might be alien life on the surface.
The relative abundance of these three molecules in Earth’s atmosphere, for example, cannot be explained by any non-biological processes.
“With the Habitable Worlds Observatory, we’ll be able to examine their atmospheres directly, looking for chemical patterns like oxygen and methane coexisting that are difficult to explain without biology,” Dr Balaji explained.
“That wouldn’t be absolute proof of life, but it would be the strongest evidence we’ve had yet.”
The HWO will not only try to find signs of life on distant worlds, but it will even take photos of them.
It should be able to beam back pictures of planets human astronauts could only dream of laying their eyes on.
While thousands of exoplanets have been detected, only a handful have been directly photographed.
Instead, we often rely on painted impressions of distant worlds – where artists are guided by scientists as to what the data says a planet might look like.
An artist’s impression of Kepler-186f, an Earth-size planet orbiting a distant star[/caption]
Current plans indicate that HWO – a large spacecraft similar to Hubble or Webb space telescopes – should be able to image a planet that is 10billion times fainter than its host star.
Scientists also believe that HWO will also be able to detect Earth-like moons of giant extrasolar planets, and spot eclipses of giant planets and their lunar satellites.
Funding pressures are real. And such ambitious missions are always vulnerable to delays.
Dr Shyam Balaji, a theoretical physicist at King’s College London
The idea for HWO was first pitched some 15 years ago, and has since snowballed into becoming “the first specifically engineered to identify habitable, Earth-like planets… and examine them for evidence of life,” according to Nasa.
By the time project jumps from paper into real-life, tangible tech, the HWO – or the core parts of the idea, at least – will be roughly 50 years old.
That’s if the mission survives President Donald Trump‘s proposed cuts to Nasa, in which the US space agency is forecast to lose nearly 20 per cent of its workforce.
But experts are cautiously hopeful that HWO will make it off the ground.
“Funding pressures are real,” said Dr Balaji. “And such ambitious missions are always vulnerable to delays.”
“But the scientific case is compelling and public interest is high,” he added.
“So I think it has a good chance of moving forward even if the schedule slips.”
Deputy executive director of the Royal Astronomical Society, Dr Robert Massey, said: “I think the value of it is so big, that it’s just a really exciting mission.
“I don’t want to sit there and say this should be funded over something else, because that’s the thing we have to avoid doing. But if it goes ahead, it will be an incredibly exciting project.”
This artists impression shows a view of the surface of the planet Proxima Centauri b[/caption]
While Earth is the only planet known to host life, scientists estimate there could be hundreds of millions of potentially habitable worlds in our galaxy, the Milky Way.
These worlds are very far away from Earth – with the closest potentially habitable world, Proxima Centauri b, located 4.2 light-years away.
To spot these planets, even through the glare of their nearest star, HWO will need some next-generation instruments on board.
Of the many instruments that HWO will have installed, it will need a tool to block out scattered light.
“If you put your thumb up in front of the sun, you can sort of look around it. The problem you have is that we’ve got an atmosphere so all the sunlight scatters,” Dr Massey explained.
“But if you do that in space, block out the light of the star, there’s no atmosphere.
“If you get the size of that right, then you could see planets in orbit around that star – and actually study them and look for the chemistry of their atmosphere.”
Of the many instruments that HWO will have installed, it will need a tool to block out scattered light[/caption]
Like Hubble and Webb, HWO will have a large mirror to help with detecting and imaging distant worlds.
The primary mirror will be at least six metres in diameter, so it needs to be segmented one way or another.
No decisions have yet been made on the detailed design of either mirror, telescope or spacecraft.
Whether we find life or not, the implications will be transformational – not just for space science, but for our understanding of humanity’s place in the universe.
Dr Caroline Harper, head of space science at the UK Space Agency
Though HWO is expected to be pretty large – and will require a powerful rocket like Nasa’s Space Launch System, SpaceX’s Starship or Blue Origin’s New Glenn to launch it into space.
The European Space Agency (ESA) and UK Space Agency (UKSA) are interested in becoming partners in the project, just like they are on the Webb telescope.
Speaking at Nasa’s Habitable Worlds Observatory conference in Washington, DC, earlier this week, Dr Harper promoted the UK’s ambition to lead an instrument on the mission.
“The UK has developed exceptional expertise in exoplanet science and cutting-edge instrumentation,” she said.
“We now have the chance to build on these strengths and take part in what could be the most significant scientific discovery in human history.
“Whether we find life or not, the implications will be transformational – not just for space science, but for our understanding of humanity’s place in the universe.”
Rocky planet Earth-like planet, Proxima Centauri b[/caption]
All you need to know about planets in our solar system
Our solar system is made up of nine planets with Earth the third closest to the Sun. But each planet has its own quirks, so find out more about them all…
- How old is Earth? Plus other facts on our planet
- How many moons does Mercury have?
- What colour is Venus?
- How far away is Mars to Earth? And other facts on the red planet
- How big is Jupiter?
- How many moons does Saturn have?
- Does Uranus have rings?
- How many moons does Neptune have?
- How big is Pluto?
- How hot is the Sun?
