A STAR'S LIFE
     
 
 
star formation
 
Dr. Michio Kaku is a theoretical physicist, best-selling author, and popularizer of science. He’s the co-founder of string field theory (a branch of string theory), and continues Einstein’s search to unite the four fundamental forces of nature into one unified theory.
The National Aeronautics and Space Administration (NASA) is the United States government agency responsible for the civilian space program as well as aeronautics and aerospace research.

President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA's predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.

Since that time, most US space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle, the Space Launch System and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches.

Take the journey into the Orion Nebula for a look at the birth, life, death of a star, a star is born – literally. The star begins as a cloud of gas and dust to its eventual end. They devour each other and end their lives by scattering gas and dust across the cosmos. Aging bright stars in the cluster glow in intense shades of red and blue. The majority of middle-aged stars, several billions of years old, are whitish in color. A myriad of far distant background galaxies of varying shapes and structure are scattered around the image.

The most intriguing object, however, doesn’t seem to belong in the cluster. It is a faint green bubble near the bottom center of the image. This so-called ‘planetary nebula’ is the aftermath of the death of a star. The burned-out central star can be seen inside the bubble. It is uncertain whether the planetary nebula is a member of NGC 1846, or simply lies along the line of sight to the cluster. Measurements of the motion of the cluster stars and the planetary nebula’s central star suggest it might be a cluster member.

In the last stages of a sunlike star's 10 billion-year life, its hydrogen fuel runs out, and the stellar core begins to shrink and heat up. The star's outer layers are blown off and set aglow by the star's radiation, creating colorful shells of gas. When 18th-century astronomers looked at such stars through small telescopes, the extended shells looked like fuzzy planetary disks. That led observers to call the objects "planetary nebulae."

Even after astronomers understood what was really going on, the name stuck. Planetary nebulae that look like butterflies, cat's eyes, rings or glowing orbs rank among the most beautiful and awe-inspiring images in Hubble's collection. The Hubble team highlights yet another example of the genre.

 

The nebula's formal name is IRAS 19475+3119. It was imaged by Hubble's Advanced Camera for Surveys back in 2003, and is actually classified as a "preplanetary nebula" (abstract) because it's in the early stages of its blow-off. The newly released image has been compared to a "beautiful bird," and for that reason I'd propose that IRAS 19475+3119 be designated the Dying Swan Nebula.
It also helps that the dying star lies in the constellation Cygnus (the Swan), 15,000 light-years from Earth in the plane of the Milky Way galaxy.

Stars are born in nebulae. Huge clouds of dust and gas collapse under gravitational forces, forming protostars. These young stars undergo further collapse, forming main sequence stars.

Stars expand as they grow old. As the core runs out of hydrogen and then helium, the core contacts and the outer layers expand, cool, and become less bright. This is a red giant or a red super giant (depending on the initial mass of the star).

It will eventually collapse and explode. Its fate is determined by the original mass of the star; it will become either a black dwarf, neutron star, or black hole.

the birth the death