Solar System Sun
Terrestrial Planet Mercury, Venus, Earth (Moon), Mars
Asteroid Belt Ceres, Vesta
Jovian Planet Jupiter, Saturn, Uranus, Neptune
Kuiper Belt Pluto, Haumea, Makemake
Scattered Disc Eris, Sedna, Planet X
Oort Cloud Etc. Scholz’s Star
Small Body Comet, Centaur, Asteroid
- 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
- To touch the Sun (6/1/2017) - The big “space” news this week is that NASA has announced that they renamed the Solar Probe Plus spacecraft the “Parker Solar Probe” in honor of Eugene N. Parker, the astrophysicist from the University of Chicago who predicted the solar wind. The probe is scheduled to launch next summer and become the first mission to … Continue reading To touch the Sun
- 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…
star : a self-luminous gaseous spheroidal celestial body of great mass which produces energy by means of nuclear fusion reactions — Webster
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
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
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.
Moon-forming disk discovered around distant planet
on July 11, 2019 at 7:09 pm
Using Earth's most powerful array of radio telescopes, astronomers have made the first observations of a circumplanetary disk of gas and dust like the one that is believed to have birthed the moons of Jupiter. […]
Exactly how fast is the universe expanding?
on July 9, 2019 at 3:02 pm
The collision of two neutron stars (GW170817) flung out an extraordinary fireball of material and energy that is allowing a a team of astrophysicists to calculate a more precise value for the Hubble constant, the speed of the universe's expansion. Previous estimates put the value between 66 and 90 km/s/Mpc, which this team refined to between 65.3 and 75.6 km/s/Mpc. […]
Massive stars grow same way as light stars, just...
on July 8, 2019 at 3:25 pm
Astronomers obtained the first detailed face-on view of a gaseous disk feeding the growth of a massive baby star. They found that it shares many common features with lighter baby stars. This implies that the process of star formation is the same, regardless of the final mass of the resulting star. This finding paves the way for a more complete understanding of star formation. […]
Black hole brings down curtain on jellyfish...
on July 3, 2019 at 1:13 am
Astronomers have studied the role of an excited black hole in the death of an exotic 'jellyfish' galaxy. The supermassive black hole at the center of jellyfish galaxy JO201 is stripping away gas and throwing it out into space, accelerating suppression of star formation and effectively 'killing' the galaxy.&nbs […]
Atmosphere of midsize planet revealed by Hubble,...
on July 2, 2019 at 8:46 pm
Two NASA space telescopes have identified the detailed chemical 'fingerprint' of a planet between the sizes of Earth and Neptune. No planets like this can be found in our own solar system, but they are common around other stars. […]
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Star formation may be halted by cold ionized...
on July 10, 2019 at 10:41 am
For the first time ionized hydrogen has been detected at the lowest frequency ever towards the center of our Galaxy. The findings originate from a cloud that is both very cold (around -230 degrees Celsius) and also ionized, something that has never been detected before. This discovery may help to explain why stars don't form as quickly as they theoretically could. […]
3-D holograms bringing astronomy to life
on July 1, 2019 at 11:00 pm
Scientists working on unravelling the mysteries of star cluster formation have found an innovative way of sharing their work with the general public. Taking inspiration from a 19th century magic trick, researchers from the University of Leeds have developed 3-D holograms that allow people to watch massive stars forming before their eyes. […]
Researchers decipher the history of supermassive...
on June 28, 2019 at 4:05 pm
Astrophysicists at Western University have found evidence for the direct formation of black holes that do not need to emerge from a star remnant. The production of black holes in the early universe, formed in this manner, may provide scientists with an explanation for the presence of extremely massive black holes at a very early stage in the history of our universe. […]
Plant seeding and panspermia
on June 27, 2019 at 12:51 pm
The first detection of an interstellar asteroid/comet-like object visiting the Solar system two years ago has sparked ideas about the possibility of interstellar travel. New research from the Technion–Israel Institute of Technology suggests that such objects also raise far reaching implications about the origins of planets across the galaxy, and possibly even the initial formation of the Solar system itself. […]
Scientist develops novel algorithm to aid search...
on June 25, 2019 at 1:45 pm
Inspired by movie streaming services such as Netflix or Hulu, a Southwest Research Institute scientist developed a technique to look for stars likely to host giant, Jupiter-sized planets outside of our solar system. She developed an algorithm to identify stars likely to host giant exoplanets, based on the composition of stars known to have planets. […]