There are so many astronomical objects out there behaving in mysterious ways that astronomers are still trying to figure out. A brand new set of words and language has to be invented every time something is discovered and that is part of what makes the study of space so interesting. There’s so much out there that is waiting to be found.
The use of mythological and ancient names to name all the objects that are in space has also always given astronomy an air of mystery and wonder that attracts all kinds of people and incentivizes them to look at the sky every night.
There are so many space-related words and terms that it is hard to keep up.
This is why below, we have compiled a list of space words that start with H so you can learn more about the study of the universe. These are words that are related to astronomy and space, if what you are looking for is specifically for name ideas or the names of objects, check out our lists of star names, planets, or constellations. You will also find those sorted by letter.
| Word | Meaning |
|---|---|
| Hadley Cell | A large-scale atmospheric circulation pattern on a planet, contributing to weather and climate systems. |
| Halley’s Comet | A famous periodic comet that orbits the Sun roughly every 76 years, visible from Earth with the naked eye. |
| Halo | A spherical region of stars or other objects that surrounds a galaxy, often containing globular clusters. |
| Halo Stars | Stars in a galaxy’s halo, often consisting of older and metal-poor stars that orbit in the outskirts of the galaxy. |
| Haro Object | A type of small nebula associated with newly formed stars, often exhibiting bright knots of gas and dust. |
| Haumea | A dwarf planet in the Kuiper Belt, known for its elongated shape and rapid rotation. |
| Hawking Radiation | The theoretical radiation emitted by black holes due to quantum effects near their event horizons. |
| Heart Nebula | A star-forming region in the constellation Cassiopeia, shaped like a heart when observed in certain wavelengths. |
| Heavy Elements | Elements with atomic numbers higher than hydrogen and helium, often formed in stellar nucleosynthesis. |
| Helical Motion | A spiral or helix-like path followed by a celestial object, often seen in the motion of some galaxies and cosmic structures. |
| Heliocentric | A model or system that places the Sun at the center, such as the heliocentric model of the solar system. |
| Heliopause | The boundary region where the solar wind from the Sun meets the interstellar medium, marking the outer extent of the heliosphere. |
| Helioseismology | The study of solar oscillations and vibrations to understand the interior structure and dynamics of the Sun. |
| Heliosheath | The outer region of the heliosphere, where the solar wind slows down and interacts with interstellar matter. |
| Heliosphere | The region of space surrounding the Sun, where its influence extends and interacts with the interstellar medium. |
| Helium Flash | A brief stage in the evolution of low-mass stars where helium ignites into nuclear fusion in the core. |
| Helix Cluster | A young star cluster in the constellation Aquarius, associated with the Helix Nebula. |
| Helix Nebula | A large planetary nebula located in the constellation Aquarius, resembling a cosmic “eye.” |
| Helmi Stream | A group of stars in the Milky Way that might be remnants of a dwarf galaxy that merged with our galaxy. |
| Herbig-Haro Object | A type of small, short-lived astronomical object formed when a young star ejects material that interacts with surrounding gas and dust. |
| Hercules | A constellation representing the mythical hero Hercules, known for its globular cluster Messier 13 (M13). |
| Herschel Space Observatory | A space-based infrared telescope used to study the universe in far-infrared and submillimeter wavelengths. |
| Hertzsprung Gap | A region on the Hertzsprung-Russell diagram where few stars are found, caused by the evolutionary paths of stars. |
| Hertzsprung-Russell Diagram | A graph that plots the luminosity (brightness) of stars against their surface temperature. |
| Hill Sphere | The region around a celestial body where its gravitational influence dominates over that of another nearby body. |
| Hill Stability | The measure of a planet’s or moon’s stability in a multi-body system, such as a planet-moon system’s relative positions. |
| Hind’s Crimson Star | A nickname for the variable star R Leporis, which can appear deep red in color during certain phases of its pulsations. |
| Hohmann Transfer Orbit | An elliptical orbit used to transfer a spacecraft between two circular orbits of different radii. |
| Horned Galaxy | A galaxy with prominent extensions resembling “horns” that project from its main body, often observed in interacting systems. |
| Horsehead Nebula | A dark nebula in the constellation Orion that appears to resemble the head of a horse. |
| Hot Jupiter | A type of exoplanet that is similar in size to Jupiter but orbits very close to its parent star, resulting in high temperatures. |
| Hourglass Nebula | A bipolar nebula in the constellation Musca, exhibiting a distinctive hourglass shape. |
| Hubble Parameter | The rate of expansion of the universe, denoted by the symbol H?, a fundamental parameter in cosmology. |
| Hubble Space Telescope | A powerful space telescope launched in 1990 that has provided stunning images and data about the universe. |
| Hubble Volume | A region of the universe centered around an observer beyond which objects are receding at speeds faster than the speed of light due to cosmic expansion. |
| Hubble’s Law | The observation that the recessional velocity of galaxies is proportional to their distance from us, indicating the expansion of the universe. |
| Hubble’s Variable Nebula | A reflection nebula in the constellation Monoceros, with a central star that causes changes in its appearance over time. |
| Huygens Probe | A space probe that landed on Saturn’s moon Titan, part of the Cassini-Huygens mission. |
| Hyades | A star cluster in the constellation Taurus, often considered the “head” of the celestial bull. |
| Hydra | The largest of the 88 modern constellations, representing a water serpent or snake. |
| Hydra-Centaurus Supercluster | A massive supercluster of galaxies that includes the Hydra and Centaurus clusters, among others. |
| Hydrostatic Equilibrium | A balance between gravitational forces pulling inward and pressure pushing outward in a celestial object. |
| Hydrostatic Escape | The process by which lighter gases at the top of a planet’s atmosphere can escape into space due to thermal motion. |
| Hygiea | The fourth-largest asteroid in the asteroid belt, located between Mars and Jupiter. |
| Hyperion | A moon of Saturn known for its irregular shape and sponge-like appearance, with a diverse surface. |
| Hypernova | An extremely energetic stellar explosion that is more powerful than a supernova. |
| Hypervelocity | Extremely high velocity, often used to describe the speed of objects such as meteoroids entering a planet’s atmosphere. |
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