Life Beyond Earth Exploration

A situation where the universe expands at a rate too fast for galaxies to form.

A situation where the universe expands at a rate too slow, causing it to eventually collapse.

The finely tuned balance of the strengths of different fundamental forces in the universe, essential for the existence of stars, galaxies, and life.

The study of organisms that thrive in extreme environments, such as hot springs, deep-sea vents, or very salty lakes.

The idea that intelligent life exists beyond Earth in the vast universe.

A system of thought suggesting that Earth is the center of the universe. It was popularized by Ptolemy and remained the accepted model for many centuries.

The idea that the sun is at the center of the universe, with the Earth and other planets revolving around it. This model was proposed by Copernicus and later supported by Kepler and Galileo.

The movement of the Earth around the sun in an elliptical path.

The speed of a planet in its orbit changes based on its distance from the sun. The closer to the sun, the faster it moves; the farther from the sun, the slower it moves.

The relationship between the distance of a planet from the sun and its orbital period. The farther a planet is from the sun, the longer it takes to complete one orbit.

The apparent change in the position of a nearby object against a distant background when viewed from different locations.

A major shift in scientific thinking that occurred during the Renaissance. Challenged the geocentric model and led to new observations and theories about the universe.

A scientist in the 16th century who used a naked-eye observatory to collect data about astronomical objects. His observations were crucial for Kepler's work on planetary orbits.

A scientific theory is a well-substantiated explanation of some aspect of the natural world that can incorporate facts, laws, inferences, and tested hypotheses.

Facts in science are observations or measurements that have been repeatedly confirmed and are generally accepted as true.

A scientific theory is a model that explains a phenomenon, often by incorporating facts, laws, and tested hypotheses. It is supported by evidence and can be used to make predictions.

Newton's Law of Universal Gravitation states that every particle in the universe attracts every other particle with a force that is proportional to the product of their masses and inversely proportional to the square of the distance between them.

Einstein's Theory of Relativity is a theory of gravitation that describes the universe at its largest scales and in the strongest gravitational fields. It explains phenomena that Newton's theory cannot, such as the bending of light by massive objects.

Scientific theories are tested to see if they can accurately predict observations. A theory can never be proven true beyond doubt, because there is always the possibility of future observations contradicting it.

A scientific theory that is more accurate and comprehensive can replace an older theory, but the older theory is not necessarily wrong. It may still be a useful approximation in certain situations.

Even though Einstein's Theory of Relativity has been very successful, scientists are still searching for a better theory of gravity that can explain the universe at all scales, especially in extremely strong gravitational fields.

Planets orbit the Sun in a counter-clockwise direction when viewed from above the North Pole. This is the same direction as the Sun's rotation.

Planets have nearly circular orbits around the Sun, not elongated or oval-shaped.

Most planets rotate on their axis in a counter-clockwise direction when viewed from above the North Pole.

Dwarf planets are large enough for their gravity to make them spherical but haven't cleared their orbit of other material.

Asteroids are rocky, weakly bound bodies that orbit the Sun. They're not massive enough to be spherical and often share their orbits with other asteroids.

Comets are like icy asteroids. They're typically found farther from the Sun and sometimes pass close, releasing dust and ice to form tails.

The Oort cloud is a hypothetical spherical cloud of icy objects that surrounds our solar system. It's thought to be the source of many long-period comets.

The Close Encounter Model proposed that planets were formed from debris due to a close encounter with a passing star. It suggests planets formed from blobs of gas pulled away from the Sun by the star's gravity.

The point in a protoplanetary disk where temperatures are low enough for volatile compounds (water, methane, ammonia) to freeze into ice.

The process by which gas in the protoplanetary disk is drawn together by gravity to form planets, particularly in the outer regions where ice cores form.

The core of a protostar undergoing nuclear fusion, generating enough energy to counteract gravitational collapse.

The process where photons generated by collisions between molecules in a protostar's core radiate away energy, preventing its collapse and allowing it to become denser.

The theory that explains the formation of our solar system from a cloud of gas and dust.

The formation of large, gaseous planets like Jupiter and Saturn, enhanced by the presence of ice beyond the frost line.

The leftover planetesimals that did not become planets, contributing to the asteroid belt, Kuiper belt, and Oort cloud.

The process where the Moon formed alongside Earth, possibly from a giant impact or a splitting of the Earth.

The idea that our planet Earth is not unique in the vastness of the universe. There are likely countless other planets, making Earth just one among many.

The laws of physics that govern the universe are consistent throughout, despite the vast distances and diverse environments within it.

The process of star formation naturally leads to the creation of planets. As stars are born, swirling gas and dust around them coalesce into planets.

Planets differ based on their composition, geological activity, and atmospheric conditions. Some are rocky, while others are primarily composed of gas.

The sheer number of stars in the universe suggests that a significant proportion of them should host habitable planets, based on our understanding of planet formation and the conditions necessary for life.

The chemical processes that led to the emergence of life on Earth might not be unique. Similar organic molecules have been found in meteorites and interstellar space, suggesting a common origin of prebiotic chemistry.

The transition from simple chemistry to complex biological systems might be a common process, given that microscopic life thrives in a wide range of extreme conditions on Earth.

The universality of the laws of chemistry implies that the same atoms and molecules are present throughout the universe, making the building blocks of life common across different celestial bodies.