NASA's impending space mission may potentially uncover extraterrestrial life beyond our solar system.
Peer Beyond the Blue Marble
Hey there! Ever wonder if there's life amidst the cosmic sea out there? Most scientists reckon it's gotta be inevitable, given our Universe's vastness.
Our Universe sprawls across space and time, so anything that could happen probably has happened more than once. In other words, chances are life isn't just limited to Earth.
The Universe, ya see, is brimming with planets, and the building blocks for life crop up everywhere we look. But how life first bloomed remains a mystery. Given the odds, though, it's highly unlikely it happened just once.
Venturing into Habitable Realms
But alas, no indisputable evidence of extraterrestrial life has been discovered yet. That might change in the next couple of decades or so with the birth of the Habitable Worlds Observatory (HWO), a future telescope destined to scour the skies for neighbors.
The HWO project officially entered its pre-Phase A stage on 1 August 2024 with the opening of the HWO Technology Maturation Project Office at NASA's Goddard Space Flight Center in Greenbelt, Maryland.
In simple terms, the HWO will be designed to identify "habitable, Earth-like planets" and examine them for hints of life.
Striking Gold Among the Stars
Ever since the first exoplanet was discovered orbiting a Sun-like star in 1995, astronomers have been unearthing more than 7,000 of these strange worlds. Despite Earth-like planets being harder to spot than giants like Jupiter, we've still managed to find a fair few.
Exoplanets like Proxima b circling the closest star to our Sun and the seven planets orbiting the star TRAPPIST-1 (about 40 lightyears away), three of which are within the star's so-called "Goldilocks zone"—an area where surface temperatures allow liquid water to exist. In our Milky Way Galaxy alone, there might be 20 billion similar potentially habitable planets.
But how do you tell if these remote worlds harbor life? The secret lies in "biomarkers"—chemicals in a planet's atmosphere, like oxygen, ozone, and methane, that suggest biological activity on the planet's surface. These chemicals leave telltale signs in the light of a planet's host star when the planet passes in front of it, causing the star's light to also include light reflected from the planet.
Using this method, known as transit spectroscopy, the James Webb Space Telescope (JWST) has already detected carbon dioxide, water vapor, and sulfur dioxide in the atmospheres of giant, gaseous exoplanets and so-called super-Earths. Identifying biomarkers on potentially habitable, Earth-like planets, however, is a much more challenging task, and JWST isn't powerful enough to do it. That's where the HWO comes in.
Building the Life-Finder
The HWO's mission traces back at least 15 years to plans presented by Goddard scientists for a huge Advanced Technology Large-Aperture Space Telescope (ATLAST). Subsequent concept studies led to two more realistic designs: the Large Ultraviolet Optical Infrared Surveyor (LUVOIR), led by Goddard, and the Habitable Exoplanet Observatory (HabEx), led by NASA's Jet Propulsion Laboratory.
The HWO will blend elements from both projects, focusing not only on the search for biomarkers but also on astrophysics. The new facility received a strong endorsement from the latest Decadal Survey on Astronomy and Astrophysics (2020), a community-driven recommendation on US government funding.
Launch and Mission
The HWO probably won't take flight before the early 2040s. A powerful rocket—like NASA's Space Launch System, SpaceX's Starship, or Blue Origin's New Glenn—will send the telescope to Lagrange 2 (L2), a region about 1.5 million kilometers (0.9 million miles) 'behind' Earth, as seen from the Sun (and home to the James Webb Space Telescope).
The HWO's primary mirror will measure at least six meters in diameter, so it'll need to be segmented in some fashion. Design details, however, have yet to be ironed out. What we do know is that the HWO will observe the same wavelength range as Hubble—from ultraviolet through the optical into the infrared. At least three large scientific instruments are planned: a high-resolution, widefield imaging camera, an ultraviolet multi-object spectrograph, and a coronagraph to block starlight and reveal the faint images of closely orbiting exoplanets.
A fourth instrument is still being defined. The coronagraph will be the most important instrument for exoplanet studies. In the past, similar instruments have been used to capture the Sun's corona by blocking the bright light of the Sun's disc. NASA's Nancy Grace Roman Space Telescope, set to launch in 2027, also utilizes a coronagraph for exoplanet observation, so engineers will have plenty of experience with the technology by the time the HWO is constructed.
Servicing the Cosmic Observer
Unlike the Hubble Space Telescope, launched into low Earth orbit back in 1990 and serviced by space shuttle astronauts multiple times, the James Webb Space Telescope can't be serviced due to operating from L2, a region four times more distant than the Moon. The HWO, however, will be designed for servicing, not by astronauts but by robots. An uncrewed mission will fly to L2, rendezvous with the HWO, and carry out necessary repairs or replacements. What's more, the mission will also install a possible second generation of science instruments, upgrading the spacecraft's capabilities.
Prospects Unveiled by the HWO
The HWO will target at least 25 nearby habitable planets for detailed study, examining their atmospheres to search for biomarkers. According to NASA's director of astrophysics, Mark Chaplin, discovering signs of life would be "the biggest revolution since Copernicus." The HWO's ultra-sharp imaging capabilities could also detect Earth-like moons or ring systems of giant extrasolar planets, and observe mutual transits and eclipses of giant planets and their moons.
A Cosmic Quest
But before the HWO can assemble the stars and planets into a living, breathing tapestry, many new technologies still have to be developed and demonstrated. So, are you excited about the HWO? Could it be the mission to turn science fiction into reality? Let us know your thoughts!
- The Universe's vastness suggests that life beyond Earth might be inevitable, considering the multitude of galaxies, planets, and the universe's infinite possibilities.
- With the upcoming birth of the Habitable Worlds Observatory (HWO), scientists hope to discover neighbors and potential life in the vast cosmic seas.
- The HWO will be instrumental in identifying habitable, Earth-like planets and examining them for signs of life, using a method called transit spectroscopy to detect biomarkers in their atmospheres.
- In the cosmic quest for life, the HWO will build upon the successes of previous space technology, blending elements from concepts like ATLAST, LUVOIR, and HabEx.
- The HWO will observe a wavelength range similar to the Hubble Space Telescope and will feature at least three large scientific instruments: a high-resolution, widefield imaging camera, an ultraviolet multi-object spectrograph, and a light-blocking coronagraph to reveal the faint images of exoplanets.
- Unlike the Hubble Space Telescope, the HWO will be designed for robotic servicing during its mission, not requiring human astronauts for repairs or replacements.
- The discovery of life beyond Earth by the HWO would lead to the biggest revolution in science since the time of Copernicus, shedding light on our place in the universe and our role as stewards for Earth's environmental-science and space-and-astronomy endeavors.
