Searching for extraterrestrial life and measuring pharmaceuticals with a self-built Raman spectroscopy device
How can we better investigate whether extraterrestrial life exists? Physicist Bram Mooij developed a new technique to make this investigation better and faster.
In the search for extraterrestrial life, Mars plays an important role. This is mainly due to its favorable position—namely that it is “easy” to travel to—and because Mars once had a climate comparable to that of Earth. To demonstrate whether extraterrestrial life is present, scientists look for so-called biomarkers. In the context of Mooij’s research, this specifically refers to substances, molecules, that are created through the intervention of living organisms.
New technique for better measurement
The conditions on the surface of Mars are extreme: it is very dry and the radiation level is high. “In places on Earth with similar conditions, we see that organisms hide beneath the surface. One way to detect the biomarkers in these organisms is Raman spectroscopy. This technique works as follows: you aim a laser at something and analyze the light that comes back. From this, you can determine which substances are present,” Mooij explains.
This technique is already widely used for chemical analysis, but usually not to measure through a rock. “To make this possible anyway, we built a special Raman spectroscopy device,” Mooij continues. “It contains a very powerful pulsed laser and also pulsed detection. The laser switches on very briefly eighty million times per second, and eighty million times per second the light is briefly allowed through to the detector.” When measuring from the surface, light from a deeper layer takes slightly longer to return than light from the surface. By scanning over this time difference, a kind of echo with light can be created. In addition, this pulsing ensures that the influence of unwanted light sources is limited.
Faster measurement setup
After this pulsed variant was completed, the researcher adapted the measurement setup to enable very fast measurements for entirely different, Earth-based applications. Initially, only a very small surface—smaller than a single bacterium—was measured at a time. As a result, scanning a large surface could take hours to days. With the new setup, a larger surface (millimeters) can be measured in one go. This means that a measurement that would take a day using traditional methods can now be carried out in just a few seconds.
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