Aliens in the Universe By Brett Keane

The universe is indeed a closed system, meaning that the total amount of energy and matter in it remains constant. However, this does not mean that the distribution and form of energy and matter are also constant. The universe is constantly changing and evolving, with stars forming and dying, galaxies colliding and merging, and planets orbiting and rotating. Therefore, the conditions for life may also change and vary throughout the universe.

Aliens are hypothetical life forms that originate from planets or other celestial bodies other than Earth. There is no definitive answer to whether aliens exist or not, as we have not yet detected any conclusive evidence of extraterrestrial life. However, many scientists believe that the universe is so vast and diverse that it is likely that life exists somewhere else besides Earth. NASA is one of the leading agencies that searches for signs of life beyond Earth, using various missions and instruments to explore the solar system and beyond¹.

One of the ways that NASA searches for life is by looking for habitable planets, or exoplanets, that orbit other stars. Habitable planets are those that have the right size, temperature, atmosphere, and water to support life as we know it. NASA uses telescopes such as TESS and Hubble to detect exoplanets by observing how they dim the light of their host stars when they pass in front of them. NASA also plans to use the upcoming James Webb Space Telescope to study the atmospheres of exoplanets and look for biosignatures, or chemical clues that indicate the presence of life¹.

Another way that NASA searches for life is by looking for technosignatures, or signs of technology that could indicate intelligent life. Technosignatures are a type of biosignature that could include radio signals, laser pulses, megastructures, or spacecraft. NASA funds research into technosignatures, but does not conduct ground-based searches for them due to its policy of using space-based assets. One example of a technosignature search is SETI (Search for Extraterrestrial Intelligence), which uses radio telescopes to scan the sky for narrow-band radio signals that could be sent by alien civilizations¹.

However, searching for life in the universe is not easy or straightforward. There are many challenges and uncertainties involved, such as the distance and time involved in communicating with other worlds, the diversity and adaptability of life forms, the possibility of false positives or negatives, and the ethical and social implications of finding or not finding life. Moreover, there is no guarantee that aliens would be friendly or hostile to us, or even interested in us at all.

Therefore, while it is possible that aliens live in the universe, it is not certain or provable at this point. We can only speculate and hope that one day we will find out for sure. Until then, we can enjoy the wonder and mystery of the cosmos and our place in it.