Exploring Other Worlds
This psychedelic view of Saturn and its rings is a composite made from images taken with the Cassini spacecraft wide-angle camera using spectral filters sensitive to wavelengths of infrared light centered at 728, 752 and 890 nanometers.
In my last article I talked about the excitement of searching for other planets with the James Webb Space Telescope. Ironically, just shortly after completing the article I read about an international team of scientists that claim to have discovered two new “super-Earth” type planets. The discovery of super-Earth planets is not all that rare; there are nearly 1,600 known super-Earths. A super-Earth is a planet that is larger than Earth, but lighter than icy planets like Uranus and Neptune. They are defined as up to twice the size of Earth and up to 10 times its mass.
So what is unique about the super-Earths discovered by researchers at Belgium’s University of Liege (ULiege)? It was an accidental discovery. The team was looking to confirm the existence of planet LP 890–9b discovered by NASA. LP 890-9b is 30 percent larger than Earth and orbits a star known only as 890-9, which is a red dwarf star 1/9th the mass and 1/6th the size of the sun. It also burns cooler, at only 4,670 degrees Fahrenheit. While attempting to verify the existence of 890-9b the team discovered a second super-Earth, LP 890-9c. After researchers at ULiege completed a few calculations and determined that the planet could have liquid water and potential support life, they renamed it SPECULOOS-2c.
SPECULOOS-2c is 40 percent larger than Earth and orbits its sun in 8.5 days. Francisco Pozuelos, a researcher at the Institute of Astrophysics of Andalusia made the original claims that the planet could be suitable to sustain life. Even though the planet is only 3.7 million miles from its sun, it receives around the same amount of stellar radiation as the Earth. In comparison the Earth is 93 million miles away from the Sun.
NASA’s Transiting Exoplanet Survey Satellite (TESS) searches for exoplanets orbiting nearby stars by monitoring the light level of thousands of stars. TESS watches for fluctuations in the intensity of light coming from these distant stars that occur on a periodic basis. It is known from observation of our own sun that when a planet of significant size passes between a star and the observer, it will cause the star to dim. This dimming will happen only once during a planet’s orbit around the distant star.
TESS has a difficult problem to solve. Determining the period of a planetary orbit in this manner would require observing multiple orbits. This means TESS must observe the stars for multiple years, or find planets with short orbital periods. Most exoplanets discovered by TESS have short orbital periods of a few days to a few weeks. Once TESS has discovered a potential planetary orbit, the discovery must be confirmed by observation with ground-based telescopes.
One may think that having the possibility of liquid water would be a rare trait for exoplanets, but there are approximately 50 exoplanets which may be able to support life. This raises a question that is easily answered, “Why have we never been able to contact or confirm the existence of life on any of these exoplanets?” The main reason is the distance from our planet. The closest exoplanet believed to be capable of supporting life orbits the Star Proxima Centauri. This star is 4.25 light years away. This means even traveling at the speed of light, which is the maximum known speed of any known object, it would take 4.25 years to reach the star. The fastest speed we can reach in space travel is projected to be 430,000 miles per hour by 2024. The speed of light is 670,616,629 miles per hour. This means that travel to Proxima Centauri would take over 6000 years with our current rocket technology.
The fastest practical spacecraft would be limited by the certain laws of physics to about one percent the speed of light, mainly due to the extreme energy required to bring a sufficient mass to that speed. This limits us to around 6.7 million miles per hour, which would reduce the travel time to our nearest galactic neighbor to around 425 years.
It’s fun to dream about visitors from space and tell futuristic tales of space exploration, visiting other planets, but it is not likely to occur any time in the near future. Even if we could reach one percent the speed of light, we would still be limited to visiting planets in our own solar system. Until next week, stay safe and learn something new.
Scott Hamilton is an Expert in Emerging Technologies at ATOS and can be reached with questions and comments via email to sh*******@te**********.org or through his website at https://www.techshepherd.org.
