
Spaced Out Speech
[Glossary of Terms]
We hope that you find these simple definitions useful in your understanding of the cosmos! Click the drop-down to explore more!
Black Holes
Areas of condensed matter with extreme gravity, from which not even light can escape
Composite
Two or more images/resources that when blended together, provide a more accurate depiction of an event or object.
Elliptical Galaxy
A type of galaxy formation that is condensed into a disc-like shape
Exoplanet
A planet that exists outside of our Solar System.
Fermi Paradox
The discrepancy between the high likelihood of extraterrestrial life and the lack of any evidence for it. The term was coined by physicist Enrico Fermi in 1950.
Galaxy
A grouping of stars, planets, moons, and other celestial objects held together by gravity, moving together as one.
Galaxy Cluster
Larger than galaxy groups, galaxy clusters are the largest gravitationally bound structures in the universe, composed mostly (~85%) of dark matter. They typically span 5 to 10 million light-years across!
Gravity
The force of attraction, or “pull”, that one object exerts on another, generated by mass or energy through the curvature of space-time. This fundamental and invisible force is the “primordial glue” that pulls matter together to form the stars/planets/galaxies, keeps celestial objects bound to their orbits, keeps us and our atmosphere from floating off the planet, and even creates the waves and tides of our oceans.
Hubble Space Telescope
“Hubble,” as it’s affectionately known, is a giant telescope that orbits 370 miles above the Earth and travels at about 17,000 miles per hour, taking high-resolution images. It has been operating for more than three decades and continues to make ground-breaking discoveries that shape our fundamental understanding of the universe. Hubble is a project of international cooperation between NASA and the ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope and mission operations. Lockheed Martin Space, based in Denver, also supports mission operations at Goddard. The Space Telescope Science Institute in Baltimore, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.
IMBH
“Intermediate-mass black hole”: a class of black hole with a mass between 100-100,000 solar masses; a rarity in the evolution of black holes.
James Webb Space Telescope
“JWST,” as it’s affectionately known, is the latest and largest addition to the armada of modern space telescopes. Equipped with high-resolution and high-sensitivity instruments, its claim to fame is its ability to read the infrared spectrum, making it capable of detecting deep space objects and atmospheric conditions. It’s primary mission is the discovery of potentially habitable planets. The JWST is a partnership between NASA, the ESA, and the Canadian Space Agency (CSA), built for a mere $10 billion!
Laniakea Supercluster
Discovered in 2014 at the University of Hawai’i at Manoa, Laniakea became the largest known cosmic structure. Its scale beyond anything we had imagined, scientists had to redefine superclusters by the relative velocities of their galaxies in order to account for it! It is shaped by a central gravitational focal point known as the Great Attractor. Laniakea is Hawaiian for “open skies” or “immense heaven,” and the name is well-earned. Laniakea includes not only our own Milky Way Galaxy, but roughly 100,000 others spanning 500 million light-years!
Light-Year
A measurement of distance (not time!) which equates to 5.88 trillion miles. This is the distance that light can travel in a vacuum over 365.25 days.
Milky Way Galaxy
A very special barred spiral galaxy containing 100-400 billion stars with an estimated diameter of 3,600 light-years! It is named for the hazy band of milky-white light that can be seen in the night sky, a result of the light reflected from stars in other arms of the galaxy. This structure contains the only confirmed life in the entire universe: on our very own planet Earth!
NASA
The National Aeronautics and Space Administration: an independent US government agency charged with the oversight of the civil space program. It is organized into directorates for Science, Space Operations, Exploration Systems Development, Space Technology, Aeronautics Research, and Mission Support, maintaining an extensive ground and communications infrastructure with (in 2026) a budget of $24.4 billion. It also provides foundational education in an effort to win back public trust, as it has been plagued by an onslaught of bad bureaucracy, poor management, and operational/safety issues since 1967. Despite this, it continues to have many successes and competes formidably at the international level.
Nebulae (pl.)
A nebula is a formation of dust and gasses that exists between the voids of outer space and around some celestial objects. Latin for “mist, vapor, fog, smoke, exhaliation,” they can span hundreds of light-years across! This is where the real stars are born!
Particle Horizon
The maximum distance light could have travelled to an observer since the beginning of the universe. This then defines the boundary of our observable universe, currently ~93 billion light-years in diameter. Metaphorically, infinite space.
Space-Time
A series of causal events spread across 4 dimensions: length, height, width, and time. It is not an absolute feature, being relevant to the observer’s position. The concept was created to define the causation of gravity, and implies that moving faster through space slows time itself.
Universe
Refers to the totality of all aspects of existence, including space, time, matter, and energy. The part we have confirmed spans 93 billion light-years and is considered generally flat, with the remaining unknown portion theoretically infinite. It is supposed to have sprung from a singular hot and dense point some 13.8 billion years ago. Composed primarily of dark matter, the universe continues its expansion from this mysterious point of origin.
