Cosmic History & Models
This term marks either the longest period of daylight or shortest period of daylight of the year
What is a solstice?
This unit of measurement represents the average distance from the center of the Earth to the center of the Sun, used for measuring distances inside our solar system.
What is an Astronomical Unit (AU)?
Stars are born in these massive, interstellar regions of space composed of huge accumulations of gas and dust.
What is a nebula (or nebulae)?
Often described as "dirty snowballs," these bodies of ice and dust develop long, glowing tails when they near the Sun.
What is a comet?
Rocket science relies heavily on this fundamental law of physics, which states that for every action, there is an equal and opposite reaction.
What is Newton’s Third Law of Motion?
This term describes the two times each year (around March 21 and September 22) when day and night are of exactly equal length all over the world.
What is an equinox?
This unit of measurement, equal to about 9.5 trillion kilometers, represents the total distance that light can travel through space over the course of a single year.
What is a light-year?
This is the first stage of a star’s formation, occurring when a spinning cloud of gas and dust collapses and the core gets hot enough to glow.
What is a protostar?
This rocky or metallic body flies through space and is structurally distinct from ice-based comets, with many orbiting in a belt between Mars and Jupiter.
What is an asteroid?
This condition of weightlessness features greatly reduced gravitational forces, causing astronauts' bones to expand and their muscles to weaken.
What is microgravity?
This Greek philosopher proposed a geocentric, or Earth-centered, model of the universe about 2,000 years ago.
Who is Aristotle?
This coordinate measurement dictates the horizontal compass direction of a space object, where due North reads as 0° and values increase clockwise.
What is Azimuth?
When a protostar's core reaches 10,000,000 °C, this nuclear process begins, converting hydrogen into helium and releasing massive energy.
What is fusion?
This specific alignment event occurs when the Earth passes directly between the Sun and the Moon, casting a shadow across the lunar surface.
What is a lunar eclipse?
This process uses electricity to split water molecules into hydrogen and oxygen to provide breathable air for space crews.
What is electrolysis?
In 1530, this Polish astronomer disrupted the geocentric view by proposing that the Sun was at the center of the solar system.
Who is Nicholas Copernicus?
This technique combines the images of two or more telescopes to achieve the resolution of a single, massive telescope.
What is Interferometry?
This type of average-sized star, which represents a stable phase for stars like our Sun, eventually expands into a Red Giant near the end of its life.
What is a Sun-like star?
This stream of charged particles flows quickly away from the Sun in every direction, but Earth is protected from it by its magnetic field.
What is solar wind?
These types of unmanned spacecraft or remote-controlled landers carry instrumentation to explore planets too dangerous for humans.
What are space probes?
Using detailed observations, this German mathematician discovered that planetary orbits are ellipses rather than perfect circles.
Who is Johannes Kepler?
Unlike optical telescopes, these metal-mesh, dish-shaped systems analyze radiation in the radio frequency range and are completely unaffected by clouds, pollution, or daytime weather.
What is a radio telescope?
This is the spectacular, outgoing shock-wave explosion that occurs at the end of a massive star's life cycle.
What is a supernova?
Often called a "falling star," this is the specific term for a small chunk of space rock while it is actively burning up inside Earth's atmosphere.
What is a meteor?
This futuristic propulsion method uses large, ultra-thin sheets to harness the momentum of physical photons emitted by the Sun, acting much like a sailboat on water.
What are solar sails?