In search of life beyond our system
Finding a planet similar to Earth or that could be inhabited is possible. The James Webb Space Telescope is equipped with near-infrared (NIR) cameras and spectrometers that are already helping astronomers observe the chemical makeup of distant planets. In the near infrared region of the electromagnetic spectrum, many molecular signatures are detected. Spectroscopic techniques make it possible to identify the atmospheric composition of planets as they move around their star. Their sun will act as a source of light that will shine through the planet’s atmosphere. The resulting light is then compared to the energy before and after the planet has moved through the light shining towards us.
The exoplanet’s atmospheric molecules leave their molecular signature in the near-infrared regions of the electromagnetic spectrum where the telescope’s spectrometers are tuned. NASA has a great explanation of this process on their website.1 Molecular signatures are extremely faint, but many molecules are discernible with repeated measurements, and all of this data should allow scientists to determine which molecules are present and the relative amounts of each. Reports are already published. For example, carbon dioxide was identified in the atmosphere of exoplanet WASP-39b using the telescope.2
Factors needed for a habitable planet
What molecules can the telescope detect? The list includes molecules such as water, carbon dioxide, carbon monoxide, methanol, ammonia, and methane. This is a very interesting list of atmospheric molecules that seem to give some idea of the habitability of a planet. What we might forget is that these molecules are all active in the infrared, which makes them good greenhouse gases. That’s not a bad thing, but the telescope’s spectrometers can’t pick up other important vital molecules like oxygen and nitrogen. Detecting water in the atmospheres of distant planets is right in the wheelhouse of this new telescope, and many scientists are trying to set aside time on the telescope to help with this detection process.3 Information about the water content of extraterrestrial atmospheres will be extremely useful in understanding the prevalence of water in the cosmos. A recent study of the atmosphere of exoplanet VHS 1256-1257 b suggests that water is present along with silicates, methane, carbon monoxide and carbon dioxide.4 Would it be a habitable place for life?
When determining whether these planets are habitable, a whole host of chemical factors must be considered, and the telescope will provide some of those details. Unfortunately, this won’t provide the complete picture. By most reports, the general meaning of a planet’s habitability is that it resides in the habitable zone, which allows liquid water to exist. However, a planet needs more than liquid water. I would say that the presence of oxygen and nitrogen is equally important. These gases can support complex life with a small variable amount of greenhouse gases to heat the planet.
The planet can’t have too many greenhouse gases, because many of them are toxic or too heavy, and they could displace oxygen and suffocate the inhabitants. A habitable planet needs oxygen and nitrogen in almost the same proportions as on Earth. Oxygen is essential for the existence of complex and larger life forms.5 It’s possible that some microbes could exist on planets without oxygen, but creatures larger than single-celled anaerobes need oxygen to fuel their metabolism.
The importance of nitrogen, other parameters
Why is nitrogen so critical? In my study, I identified at least 10 parameters that make nitrogen the ideal partner for oxygen. Observing nitrogen with oxygen in the atmospheres of potentially habitable planets will provide a more accurate picture. Unfortunately, these diatomic molecules have their spectral signatures in the X-ray and UV region of the electromagnetic spectrum, which is not part of the telescope’s instrumentation. The planet’s atmosphere is responsible for maintaining liquid water with a pressure of about 15 psi (pounds per square inch). Dioxygen is about 3 psi, but the remaining 12 psi must come from a diatomic molecule similar in density to oxygen and must have the following attributes:
» non reactive to oxygen
» transparent in the visible/infrared
» not forming a greenhouse
» some ability to absorb harmful short-wavelength radiation (UV, X-rays and gamma rays)
» non-reactive to life (inert)
» poorly soluble in water
» non-acidifying in water
» useful for life
No other molecule matches these criteria as precisely as dinitrogen. Total air pressure is critical, as it sets the proper pressure to hold water in liquid form. Too little pressure and the water evaporates into the air, causing increased humidity, global warming and the removal of water from lakes, rivers and organisms. Too much air pressure will effectively stop the water cycle which cleans and desalinates water for reuse. For finding a habitable planet for humans, Earth’s atmosphere sets the standard for many chemical reasons.
The local star near an exoplanet must also be a good match that resembles our own sun in terms of spectral output. If the star produces too much infrared or near-infrared energy, that light does not have enough energy to drive photosynthesis and other life-sustaining chemical reactions. If the star produces too much energy in the UV range (or X-rays and gamma rays), it will destroy all molecules based on carbon, which is the only type of atom that meets the requirements for fitness for life .6
The number of parameters is quite long, making the earth a rare exception in the universe, according to some scientists.seven The telescope broadens our view and understanding of the chemical composition of exoplanet atmospheres. All of this new information will help us understand how common certain atmospheric molecules are in the universe. The scientific community will better understand the probability of finding an Earth-like planet. But will we find the equal of the earth? The telescope is a nice step in this search, but the probability seems quite low, considering all the requirements. Until we can get a full chemical profile of an exoplanet’s atmosphere, searching for water and other infrared-active gases will be a good step forward, but it won’t be the last. case.
What does the Scripture say about other habitable planets? Is there a chance that some worlds can support life? Some have suggested that the “sons of God”, mentioned in Job 1:6, 7, who visit the heavens could indicate other planets with human-like inhabitants. From the writings of Ellen White, we know that other inhabited worlds exist but are beyond our reach. In Early writings White writes: “Then the angel said, ‘You must go again, and if you are faithful, you, with the 144,000, you will have the privilege of visiting all the worlds and seeing the work of God.’ ”8 I firmly believe that there are other habitable planets, but they exist by God’s design and only by His handiwork. The telescope will help determine the possibility of a habitable planet, and this new information will help the world see the power and might of our Creator’s hand.
1 C. Pulliam, “NASA’s Webb Space Telescope to inspect the atmospheres of gas giant exoplanets”, NASA.gov, July 11, 2018, https://www.nasa. gov/feature/goddard/2018/nasa-s-webb-space-telescope-to-inspect-atmospheres-of-gas-giant-exoplanets.
2 T. Pultarova, “James Webb Space Telescope Sniffs Carbon Dioxide Around an Alien World”, Espace.com2022, https://www.space.com/james-webb-space-telescope-exoplanet-carbon-dioxide.
3 K. Cooper, “Possible Aquatic World Spotted Orbiting Alien Star”, Space.com2022, https://www.space.com/ocean-world-habitable-zone-potential-detection.
4 BE Miles et al., “The TELESCOPE: Early Release Science Program for Direct Observations of Exoplanetary Systems II: A 1 to 20 Micron Spectrum of the Planetary-Mass Companion VHS 1256-1257 b,” 2022, arXiv:2209.00620v1.
5 N.Lane, Oxygen: the molecule that created the world (Oxford: Oxford University Press, 2002).
6 Mr Denton, The Fate of Nature: How the Laws of Biology Reveal the Purpose of the Universe (New York: Free Press, 2002).
seven See, for example, G. Gonzalez and JW Richards, The privileged planet: how our place in the cosmos is designed for discovery (Washington, DC: Gateway Editions, 2020) and PD Ward and D. Brownlee, Rare earth: why complex life is rare in the universe (New York: Springer, 2000).
8 Ellen G. White, Early writings (Washington, DC: Review and Herald Pub. Assn., 1882, 1945), p. 40.