ClassX Video Lessons Do aliens exist? If they did, would we know? | NASA astronomer Michelle Thaller
One of the biggest questions we face is whether we are alone in the universe. Many scientists think that with so many stars and planets in our galaxy, there must be other forms of life out there. The Milky Way alone has about half a trillion stars, and almost every star has its own solar system, making the chances of life beyond Earth quite high.
Some stars in our galaxy are older than our sun, which means civilizations could have started billions of years before life began on Earth. If these civilizations exist, they might be more advanced than us. However, even with the vastness of the universe, we haven’t found solid proof of these alien civilizations yet.
Physicist Freeman Dyson came up with an interesting idea called the Dyson Sphere. This is a theoretical structure where an advanced civilization could capture the energy of its star by building large collectors around it. Instead of waiting for solar energy to reach their planet, they could directly collect the energy from their star.
While building a complete shell around a star might not be practical due to stability issues, a grid of orbiting collectors could work. Scientists think that if such structures exist, they might be detectable through the heat they emit.
Researchers have thought about finding Dyson Spheres by looking for infrared radiation, which is heat emitted by a star-like object without visible light. If a star were surrounded by a shell to collect energy, it might give off a lot of heat while blocking visible light. Unfortunately, no evidence of this has been found yet.
The Kepler mission, which aimed to find exoplanets by watching the brightness of stars, made a significant discovery. By observing a specific part of the sky for long periods, scientists could see slight dimming of stars caused by planets passing in front of them.
In a surprising turn, one star showed dramatic dips in brightness—up to 25%. Such a big drop in light could only be caused by something as large as another star, but no companion star was found. This strange data was first noticed by citizen scientists, who flagged it for more investigation.
The unusual shape of the dimming pattern led to questions about its cause. Some thought it might be evidence of a Dyson Sphere, but further analysis showed it was likely caused by a thick cloud of dust around the star. This dust could have come from a collision between two planets, creating a massive, uneven cloud that blocked the star’s light.
Even though we haven’t found evidence of alien civilizations, scientists are still excited about the search for extraterrestrial life. Researchers work with organizations like the Search for Extraterrestrial Intelligence (SETI) to explore potential signals from space. The excitement around these discoveries shows a real curiosity and hope for finding life beyond our planet.
While we haven’t found definitive evidence of extraterrestrial civilizations yet, the search continues to inspire scientists and enthusiasts. The universe is vast and mysterious, and the possibility of discovering life beyond Earth fuels our imagination. As we look to the stars, we remain hopeful that one day, we may find the signals or artifacts that prove we are not alone in the cosmos.
Explore the Drake Equation, which estimates the number of active, communicative extraterrestrial civilizations in the Milky Way galaxy. Research each factor of the equation and present your findings to the class. Discuss how changes in each variable might affect the overall estimate and what this means for the search for extraterrestrial life.
Using materials like cardboard, paper, and other craft supplies, create a model of a Dyson Sphere. Consider the engineering challenges and potential benefits of such a structure. Present your model and explain how it could theoretically capture a star’s energy and what implications this might have for an advanced civilization.
Use a computer simulation or a classroom activity to mimic the Kepler Mission’s method of detecting exoplanets. Observe how the brightness of a star changes when a planet passes in front of it. Discuss how this method helps scientists discover new planets and what unusual patterns might suggest about potential extraterrestrial structures.
Participate in a classroom debate on the topic “Are We Alone in the Universe?” Divide into teams to argue for and against the existence of extraterrestrial life. Use scientific evidence, theories, and current research to support your arguments. Conclude with a discussion on the implications of finding or not finding extraterrestrial life.
Examine real or simulated data from the Search for Extraterrestrial Intelligence (SETI). Analyze the signals for patterns or anomalies that might suggest intelligent origin. Discuss the challenges of distinguishing between natural and artificial signals and the importance of this work in the search for extraterrestrial life.
Search – The act of exploring or investigating to discover new information or phenomena, often in the context of scientific research. – Scientists continue their search for extraterrestrial life by analyzing data from distant planets.
Life – A characteristic that distinguishes physical entities with biological processes, such as growth and reproduction, from those that do not. – The discovery of microbial life on Mars would revolutionize our understanding of biology and the universe.
Universe – The totality of known or supposed objects and phenomena throughout space; the cosmos. – The universe is vast and expanding, filled with billions of galaxies, each containing millions of stars.
Civilization – An advanced stage of human social development and organization, often marked by the creation of cities, complex institutions, and technological advancements. – The search for extraterrestrial civilizations involves listening for signals that might indicate intelligent life beyond Earth.
Energy – The capacity to do work or produce change, existing in various forms such as kinetic, potential, thermal, and electromagnetic. – Stars emit energy in the form of light and heat, which is essential for sustaining life on nearby planets.
Evidence – Information or data that supports or refutes a hypothesis or theory, often gathered through observation or experimentation. – The presence of water vapor in a planet’s atmosphere is considered strong evidence for the potential of life.
Star – A massive, luminous sphere of plasma held together by gravity, undergoing nuclear fusion and emitting light and heat. – Our Sun is a star that provides the necessary energy for life on Earth.
Dust – Fine particles of matter, often found in space, that can form planets and stars through accumulation and gravitational attraction. – Interstellar dust plays a crucial role in the formation of new stars and planetary systems.
Planets – Celestial bodies orbiting a star, large enough to be rounded by their own gravity but not large enough to cause thermonuclear fusion. – The discovery of exoplanets in the habitable zone of their stars raises the possibility of finding life beyond our solar system.
Intelligence – The ability to acquire and apply knowledge and skills, often associated with problem-solving and adaptation to new situations. – The search for extraterrestrial intelligence involves detecting signals that might indicate advanced technological societies.
