3D holography could help spot alien life
Washington: Digital holograms — 3D images recorded using lasers — may be our best bet for finding alien life, scientists say.
No probe since Nasa’s Viking program in the late 1970s has explicitly searched for extraterrestrial life. Rather, the focus has been on finding water.
Saturn’s icy moon Enceladus has a lot of water, but even if life does exist there in some microbial fashion, the difficulty for scientists on Earth is identifying those microbes from 790 million miles away.
“It’s harder to distinguish between a microbe and a speck of dust than you’d think,” said Jay Nadeau, research professor at California Institute of Technology in the US.
Enceladus has enormous geysers, venting water vapour through cracks in the moon’s icy shell, regularly jet out into space.
When the Saturn probe
To study motion of potential microbes from Enceladus’s plumes, researchers proposed using an instrument called a digital holographic microscope, modified specifically for astrobiology
Cassini flew by Enceladus in 2005, it spotted water vapour plumes in the south polar region blasting icy particles at nearly 2,000 kilometres per hour to an altitude of nearly 500 kilometres above the surface.
To study the motion of potential microbes from Enceladus’s plumes, Nadeau proposed using an instrument called a digital holographic microscope that has been modified specifically for astrobiology. To study holograms’ potential utility for analysing extraterrestrial samples, researchers obtained samples of water from the Arctic, which is sparsely populated with bacteria.
With holographic microscopy, Nadeau was able to identify organisms with population densities of just 1,000 cells per millilitre of volume.
That low threshold for detection, coupled with the system’s ability to test a lot of samples quickly and its few moving parts, makes it ideal for astrobiology, Nadeau said.