Waiting Room

asterikos:

aprillikesthings:

museumnelson:

republicansareahategroup:

pr1nceshawn:

Taking Public Transit: Day 1 vs Day 101.

I don’t get the last one e.e

If it is empty and the other cars are full there is a reason you don’t want to learn that reason

^^^^^ 

That third one is so accurate

(Source: College Humor)

poees:

_{oh my friends, my friends forgive me
                    that I live and you are gone.}

identity-of-design:

This year’s best halloween costume goes to theses Japanese art students -

(Source: boredpanda.com)

astronomyblog:

Planetary nebula

A planetary nebula, abbreviated as PN or plural PNe, is a kind of emission nebula consisting of an expanding, glowing shell of ionized gas ejected from red giant stars late in their lives. The word “nebula” is Latin for mist or cloud, and the term “planetary nebula” is a misnomer that originated in the 1780s with astronomer William Herschel because, when viewed through his telescope, these objects resemble the rounded shapes of planets. Herschel’s name for these objects was popularly adopted and has not been changed. They are a relatively short-lived phenomenon, lasting a few tens of thousands of years, compared to a typical stellar lifetime of several billion years.

Most planetary nebulae form at the end of the star’s life, during the red giant phase, when the outer layers of the star are expelled by strong stellar winds. After most of the red giant’s atmosphere is dissipated, the ultraviolet radiation of the hot luminous core, called a planetary nebula nucleus (PNN), ionizes the ejected material. Absorbed ultraviolet light energises the shell of nebulous gas around the central star, causing it to appear as a brightly coloured planetary nebula.

Planetary nebulae likely play a crucial role in the chemical evolution of the Milky Way by expelling elements to the interstellar medium from stars where those elements were created. Planetary nebulae are observed in more distant galaxies, yielding useful information about their chemical abundances.

Stars greater than 8 solar masses (M_⊙) will likely end their lives in dramatic supernovae explosions, while planetary nebulae seemingly only occur at the end of the lives of intermediate and low mass stars between 0.8 M_⊙ to 8.0 M_⊙.

• source 
  
• images: NASA/ESA, Hubble