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.
Astrophysicists measure precise rotation pattern...
on September 20, 2018 at 8:09 pm
Scientists have measured the differential rotation on Sun-like stars for the first time, and their findings challenge current science on how stars rotate. […]
Gaia hints at our Galaxy’s turbulent life
on September 19, 2018 at 5:30 pm
Our Milky Way galaxy is still enduring the effects of a near collision that set millions of stars moving like ripples on a pond, the Gaia star mapping mission has shown. […]
Looking back in time to watch for a different...
on September 19, 2018 at 2:10 pm
A simulation has suggested what astronomers should look for if they search the skies for a direct collapse black hole in its early stages. […]
Nuclear pasta, the hardest known substance in the...
on September 18, 2018 at 3:08 pm
A team of scientists has calculated the strength of the material deep inside the crust of neutron stars and found it to be the strongest known material in the universe. […]
Magellanic Clouds duo may have been a trio
on September 18, 2018 at 1:08 pm
Two of the closest galaxies to the Milky Way -- the Large and Small Magellanic Clouds -- may have had a third companion, astronomers believe. New research describes how another 'luminous' galaxy was likely engulfed by the Large Magellanic Cloud some three to five billion years ago. […]
Phys.org - latest science and technology news stories Phys.org internet news portal provides the latest news on science including: Physics, Nanotechnology, Life Sciences, Space Science, Earth Science, Environment, Health and Medicine.
Narrowing down the mass of the Milky Way
on September 21, 2018 at 1:20 pm
Since the birth of modern astronomy, scientists have sought to determine the full extent of the Milky Way galaxy and learn more about its structure, formation and evolution. At present, astronomers estimate that it is 100,000 to 180,000 light-years in diameter and consists of 100 to 400 billion stars – though some estimates say there could be as many as 1 trillion. […]
Advancing local terahertz oscillators to enable...
on September 19, 2018 at 2:07 pm
NASA is developing a new type of detector that will provide insight into the formation and structure of the universe. Many of the radiative and mechanical interactions that shape the interstellar medium of galaxies and drive galactic evolution (e.g., shock waves from stellar winds and jets, supernova explosions, etc.) are best observed in the 4.744 terahertz (THz) spectral region for the oxygen line. Observations of this spectral line have rarely been performed, however, because the 4.744-THz […]
Magnetic waves create chaos in star-forming clouds
on September 13, 2018 at 12:34 pm
New research by Stella Offner, assistant professor of astronomy at The University of Texas at Austin, finds that magnetic waves are an important factor driving the process of star formation within the enormous clouds that birth stars. Her research sheds light on the processes that are responsible for setting the properties of stars, which in turn affects the formation of planets orbiting them, and, ultimately, life on those planets. The research is published in the current issue of the journal […]
Black hole disks may be hiding in the centers of...
on September 6, 2018 at 12:55 pm
Galactic nuclei are teeming with black holes. Earlier this year, 12 X-ray binaries were discovered at the Milky Way's center which suggested that thousands of black holes may be hiding in that region. A recent study shows that these stellar black holes are expected to orbit in a disk around the central supermassive black hole. […]
Telescope maps cosmic rays in Magellanic clouds
on September 4, 2018 at 2:15 pm
A radio telescope in outback Western Australia has been used to observe radiation from cosmic rays in two neighbouring galaxies, showing areas of star formation and echoes of past supernovae. […]