By Martin S. Hussey Jr., Correspondent
On September 27, 2021, at 7:00 p.m., the Jim and Linda Lee Planetarium hosted an hour-long show called “Beyond our Solar System.” The show was hosted by Eric Edelman, Planetarium Director at Embry-Riddle Aeronautical University, and discusses standard knowledge of exoplanet history and future possibility of living on these planets.
The show starts by discussing the planets that, with planet Earth, orbit around the Sun as a solar system. Starting with the planets closest to Earth: Venus, Mars, and Mercury. The next planets to be introduced were the gas giants Saturn and Jupiter and the frosted gas planets Uranus and Neptune. The show then goes into the 1992 discovery of “PSR B1257+12” AKA Poltergeist and “PSR B1257+12 C” AKA Phobetor (the Greek god of nightmares). These two planets are significant because they are the first two planets that orbit a star that is not the sun. These two planets, dubbed exoplanets, orbited a pulsar that was named Lich. In short, a pulsar is a rapidly rotating neutron star that forms from materials remaining after a supernova. These neutron stars usually have a mass somewhere between equal to twice as much as the Sun.
The next topic the show discussed was how these exoplanets are discovered. The first method were telescopes, be they on the ground or in space, such as the Kepler Space Telescope which detected 2500 planets before its retirement in October of 2018. Another method is simply observing shifts from other planets, the same way German astronomer Johann Gottfried Galle discovered Neptune being the gravitational pull that was tugging Uranus on September 23, 1846. Scientists also developed the “transit method” which observes the amount of light that is being viewed. Regular dips of light would indicate that there is an exoplanet orbiting.
After discussing exoplanets, the show goes on to explain how scientists can know which planets are inhabitable for humans. Not all planets are inhabitable for humans. For example, Venus might be like Earth in shape and size, but due to the thick layer of carbon dioxide clouds, extra heat is trapped on the planet which makes the environment too extreme for humans. So, scientists created a concept called the “habitable zone.” A planet would be considered a habitable zone if water can be present on it. The planet cannot be too hot that the water boils nor be too cold that the water freezes. Additionally, NASA states that there are other factors to consider. For example, some planets that would be considered habitable orbit around a red dwarf star and are prone to sterilizing stellar flames which could be hazardous to life on that planet. Humorously, this is sometimes why the habitable zone is sometimes called the “Goldilocks zone.” Scientists believe there are exoplanets out there that could be habitable, but the research continues.
Finally, the show goes into the philosophical debate of what a “planet” is. In Edelman’s words, “I think I’ve said that word so many times in this show it’s nearly lost all meaning. What exactly is a planet? As we continue to explore the galaxy, we’re finding more and more planets around more and more stars, and as we do so, just exactly what have we found that word to mean?” A planet could be defined as hot and destructive such as a hot jupiter, or it could be defined as beautiful where feats of light and storms collide. Planets could be of different shapes, colors, and densities. At the very end of it all, a planet can mean many things.
The show ends on a rather wholesome note, stating how every day we discover and learn about these new planets and even if life does not exist now, maybe one day it can. All these planets can have a role in the future of humanity. Edelman then ends the show by saying, “As we learn more about all of them, one point remains clear. There is so much waiting for us out there Beyond Our Solar System.”