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Physical Realm
Universe Astronomical Instrument
Galaxy Milky Way, Andromeda
Planetary System Star, Brown Dwarf, Planet, Moon

Solar System Sun
Terrestrial Planet Mercury, Venus, Earth (Moon), Mars
Asteroid Belt Ceres, Vesta
Jovian Planet Jupiter, Saturn, Uranus, Neptune
Trans-Neptunian Object
Kuiper Belt Pluto, Haumea, Makemake
Scattered Disc Eris, Sedna, Planet X
Oort Cloud Etc. Scholz’s Star
Small Body Comet, Centaur, Asteroid


  • Touch the Sun (12/6/2019) - Remember how Icarus wanted to touch the Sun, but met his demise instead? Well, scientists at NASA wanted to touch the Sun too, but unlike Icarus, they succeeded! Better yet, they are beginning to share what they learned by doing it! Before we get into all of that, let’s go back and start at the … Continue reading Touch the Sun
  • Halloween@NASA (10/31/2019) - The folks at NASA love Halloween, and they do something to celebrate every year. For example, the engineers at NASA Jet Propulsion Lab have been holding a pumpkin carving contest for almost a decade, and stories about their ingenuity invariably make it into the news. Here’s a video from Wired about their 2016 competition. Here’s … Continue reading Halloween@NASA
  • Get Lost in Space! (9/14/2018) - Way back in August, in anticipation of the start of a new school year, I set out to update the pages on this site related to space. Those pages tend to be popular among the teachers and students who use Cosma, and I happen to enjoy updating them, too. It sounded like a short, fun … Continue reading Get Lost in Space!
  • Milky Way Lost & Found (8/15/2018) - Have you seen the Milky Way? You may think that you have, but are you sure? Unless you live in an extremely remote area, or you’ve visited one, then you probably haven’t seen our own galaxy, the Milky Way, very well, or at all. Worse yet, you may not even realize that it’s missing. The … Continue reading Milky Way Lost & Found
  • Umbraphiles (8/20/2017) - umbraphile : One who loves eclipses, often travelling to see them. — Wiktionary Yes, this is that obligatory post about “The Solar Eclipse” (NASA, Wikipedia). Of course, there had to be one — eclipses really are just too cool to ignore. You’ve already been bombarded with explanations of the science and history of eclipses, but … Continue reading Umbraphiles
  • TRAPPIST-1 (2/23/2017) - You’ve probably heard that NASA has found a trove of “Earth-like” planets circling the TRAPPIST-1 system roughly 40 light years away, but just in case you haven’t, here’s a short 2 minute AP video about the discovery. Here’s another video from NASA/JPL with more explanation. Most entertainingly, here’s a 360° YouTube Video published by NASA/JPL … Continue reading TRAPPIST-1


These are organized by a classification scheme developed exclusively for Cosma. More…



Stars Reference (National Geographic)
Star Portal (Wikipedia)


star : a self-luminous gaseous spheroidal celestial body of great mass which produces energy by means of nuclear fusion reactions — Webster

OneLook, Free Dictionary, Wiktionary, Urban Dictionary


Roget’s II (, Merriam-Webster Thesaurus, Visuwords


Star is a luminous sphere of plasma held together by its own gravity. The nearest star to Earth is the Sun. Many other stars are visible to the naked eye from Earth during the night, appearing as a multitude of fixed luminous points in the sky due to their immense distance from Earth. Historically, the most prominent stars were grouped into constellations and asterisms, the brightest of which gained proper names. Astronomers have assembled star catalogues that identify the known stars and provide standardized stellar designations. However, most of the stars in the Universe, including all stars outside our galaxy, the Milky Way, are invisible to the naked eye from Earth. Indeed, most are invisible from Earth even through the most powerful telescopes.

For at least a portion of its life, a star shines due to thermonuclear fusion of hydrogen into helium in its core, releasing energy that traverses the star’s interior and then radiates into outer space. Almost all naturally occurring elements heavier than helium are created by stellar nucleosynthesis during the star’s lifetime, and for some stars by supernova nucleosynthesis when it explodes. Near the end of its life, a star can also contain degenerate matter. Astronomers can determine the mass, age, metallicity (chemical composition), and many other properties of a star by observing its motion through space, its luminosity, and spectrum respectively. The total mass of a star is the main factor that determines its evolution and eventual fate. Other characteristics of a star, including diameter and temperature, change over its life, while the star’s environment affects its rotation and movement. A plot of the temperature of many stars against their luminosities produces a plot known as a Hertzsprung–Russell diagram (H–R diagram). Plotting a particular star on that diagram allows the age and evolutionary state of that star to be determined.

A star’s life begins with the gravitational collapse of a gaseous nebula of material composed primarily of hydrogen, along with helium and trace amounts of heavier elements. When the stellar core is sufficiently dense, hydrogen becomes steadily converted into helium through nuclear fusion, releasing energy in the process. The remainder of the star’s interior carries energy away from the core through a combination of radiative and convective heat transfer processes. The star’s internal pressure prevents it from collapsing further under its own gravity. A star with mass greater than 0.4 times the Sun’s will expand to become a red giant when the hydrogen fuel in its core is exhausted. In some cases, it will fuse heavier elements at the core or in shells around the core. As the star expands it throws a part of its mass, enriched with those heavier elements, into the interstellar environment, to be recycled later as new stars. Meanwhile, the core becomes a stellar remnant: a white dwarf, a neutron star, or if it is sufficiently massive a black hole.

Binary and multi-star systems consist of two or more stars that are gravitationally bound and generally move around each other in stable orbits. When two such stars have a relatively close orbit, their gravitational interaction can have a significant impact on their evolution. Stars can form part of a much larger gravitationally bound structure, such as a star cluster or a galaxy. — Wikipedia

Stars (Eric Weisstein’s World of Astronomy, Wolfram Research)
David Darling’s Internet Encyclopedia of Science
Encyclopædia Britannica


Guide to Stars & Galaxies (


Stars (Wolfram Alpha)


Stellar Astronomy is the study of stars and stellar evolution, and it is fundamental to our understanding of the Universe. The astrophysics of stars has been determined through observation and theoretical understanding; and from computer simulations of the interior. Star formation occurs in dense regions of dust and gas, known as giant molecular clouds. When destabilized, cloud fragments can collapse under the influence of gravity, to form a protostar. A sufficiently dense, and hot, core region will trigger nuclear fusion, thus creating a main-sequence star. — Wikipedia



History of Stars (Universe Today)


Quotations Page


WorldCat, Library of Congress, UPenn Online Books, Open Library



Stars & Star Clusters (Ask an Astronomer, Cornell University)
Stars (Cosmos4Kids)


Crash Course Astronomy (YouTube)

OER Commons: Open Educational Resources



Science Daily,, NPR Archives








OEDILF: The Omnificent English Dictionary In Limerick Form


Song Lyrics



Stars News -- ScienceDaily News about Stars. Read science articles and see images on the birth of monstrous stars, brown dwarfs and red giants. Consider stellar evolution and more.

  • Discovery of close binary trans-Neptunian object
    on September 28, 2020 at 7:28 pm

    A new study reveals the binary nature of a trans-Neptunian object (TNO).

  • First study with CHEOPS data describes one of the...
    on September 28, 2020 at 1:05 pm

    CHEOPS keeps its promise: Observations with the space telescope reveal details of the exoplanet WASP-189b - one of the most extreme planets known.

  • Astronomers model, determine how disk galaxies...
    on September 25, 2020 at 3:34 pm

    By developing better computer simulations, researchers have determined that the scattering of stars from their orbits by the gravity of massive clumps within galaxies leads to a common look in galaxy disks -- bright centers fading away to dark edges.

  • Pair of massive baby stars swaddled in salty...
    on September 25, 2020 at 3:34 pm

    Astronomers spotted a pair of massive baby stars growing in salty cosmic soup. Each star is shrouded by a gaseous disk which includes molecules of sodium chloride, commonly known as table salt, and heated water vapor. Analyzing the radio emissions from the salt and water, the team found that the disks are counter rotating. It is promising that salt is an excellent marker to explore the immediate surroundings of giant baby stars.

  • Astronomers discover an Earth-sized 'pi planet'...
    on September 21, 2020 at 3:17 pm

    Scientists have discovered a 'pi Earth' -- an Earth-sized planet that zips around its star every 3.14 days, in an orbit reminiscent of the universal mathematics constant. - latest science and technology news stories internet news portal provides the latest news on science including: Physics, Nanotechnology, Life Sciences, Space Science, Earth Science, Environment, Health and Medicine.

  • Astronomers model, determine how disk galaxies...
    on September 25, 2020 at 1:34 pm

    Computer simulations are showing astrophysicists how massive clumps of gas within galaxies scatter some stars from their orbits, eventually creating the smooth, exponential fade in the brightness of many galaxy disks.

  • The first ultra-hot Neptune, LTT 9779b, is one of...
    on September 22, 2020 at 1:17 pm

    An international team of astronomers, including a group from the University of Warwick, have discovered the first Ultra Hot Neptune planet orbiting the nearby star LTT 9779.

  • Promising computer simulations for stellarator...
    on September 21, 2020 at 12:10 pm

    The turbulence model called Gyrokinetic Electromagnetic Numerical Experiment (GENE), developed at Max Planck Institute for Plasma Physics (IPP) at Garching, Germany, has proven to be very useful for the theoretical description of turbulence in the plasma of tokamak-type fusion devices. Extended for the more complex geometry of stellarator-type devices, computer simulations with GENE now indicate a new method to reduce plasma turbulence in stellarator plasmas. This could significantly increase […]

  • Scientist searches for stellar phosphorus to find...
    on September 16, 2020 at 2:37 pm

    A Southwest Research Institute scientist has identified stellar phosphorus as a probable marker in narrowing the search for life in the cosmos. She has developed techniques to identify stars likely to host exoplanets, based on the composition of stars known to have planets, and proposes that upcoming studies target stellar phosphorus to find systems with the greatest probability for hosting life as we know it.

  • Unraveling a spiral stream of dusty embers from a...
    on September 16, 2020 at 2:01 pm

    With almost two decades of mid-infrared (IR) imaging from the largest observatories around the world including the Subaru Telescope, a team of astronomers was able to capture the spiral motion of newly formed dust streaming from the massive and evolved binary star system Wolf-Rayet (WR) 112. Massive binary star systems, as well as supernova explosions, are regarded as sources of dust in the Universe from its early history, but the process of dust production and the amount of the ejected dust […]