The extragalactic nebula contains between two hundred and four hundred billion stars and a minimum of a hundred billion planets. the precise figure depends on the amount of very-low-mass stars, that ar arduous to find, particularly at distances of over three hundred ly (90 pc) from the Sun. As a comparison, the neighboring Andromeda galaxy contains Associate in Nursing calculable one trillion (1012) stars. The extragalactic nebula may contain maybe 10 billion white dwarfs, a billion nucleon stars, and 100 million black holes. Filling the house between the celebs may be a disk of gas and dirt referred to as the interstellar space. This disk has a minimum of a comparable extent in radius to the celebs, whereas the thickness of the gas layer ranges from many lightweight years for the colder gas to thousands of sunshine years for hotter gas.
The disk of stars within the extragalactic nebula doesn’t have a pointy edge on the far side that there are not any stars. Rather, the concentration of stars decreases with distance from the middle of the extragalactic nebula. For reasons that aren’t understood, on the far side a radius of roughly forty,000 ly (13 kpc) from the middle, the amount of stars per cubical secpar drops abundant quicker with radius. encompassing the galactic disk may be a spherical Galactic Halo of stars and globose clusters that extends more outward however is proscribed in size by the orbits of 2 extragalactic nebula satellites, the massive and tiny Magellanic Clouds, whose nighest approach to the Galactic Center is concerning one hundred eighty,000 ly (55 kpc). At this distance or on the far side, the orbits of most halo objects would be discontinuous by the Magellanic Clouds. Hence, such objects would in all probability be ejected from the locality of the extragalactic nebula.The integrated absolute visual magnitude of the assemblage is countable to be around −20.9.
Both attraction microlensing and planetary transit observations indicate that there could also be a minimum of as several planets absolute to stars as there ar stars within the extragalactic nebula, and microlensing measurements indicate that there ar additional rascal planets not absolute to host stars than there ar stars. The extragalactic nebula contains a minimum of one planet per star, leading to 100–400 billion planets, in keeping with a January 2013 study of the five-planet star system astronomer-32 with the Kepler house observatory. a unique January 2013 analysis of astronomer knowledge calculable that a minimum of seventeen billion Earth-sized exoplanets reside within the extragalactic nebula. On November four, 2013, astronomers according, supported astronomer house mission knowledge, that there may be as several as forty billion Earth-sized planets orbiting within the liveable zones of Sun-like stars and red dwarfs at intervals the extragalactic nebula. eleven billion of those calculable planets could also be orbiting Sun-like stars. the closest such planet could also be four.2 light-years away, in keeping with a 2016 study. Such Earth-sized planets could also be additional varied than gas giants. Besides exoplanets, “exocomets”, comets on the far side the system, have additionally been detected and should be common within the extragalactic nebula.