Search results
Results from the WOW.Com Content Network
The listed objects currently include most objects in the asteroid belt and moons of the giant planets in this size range, but many newly discovered objects in the outer Solar System are missing, such as those included in the following reference. [58] Asteroid spectral types are mostly Tholen, but some might be SMASS.
In November 2013, astronomers reported, based on Kepler space mission data, that there could be as many as 40 billion Earth-sized planets orbiting in the habitable zones of Sun-like stars and red dwarfs within the Milky Way. [166] [167] [168] 11 billion of these estimated planets may be orbiting Sun-like stars. [169]
The most massive to explode would be just below the Chandrasekhar limit at around 1.41 solar masses and would take of the order of 10 1100 years, while the least massive to explode would be about 1.16 solar masses and would take of the order 10 32 000 years, totaling around 1% of all black dwarfs.
Thus, the Sun occupies 0.00001% (1 part in 10 7) of the volume of a sphere with a radius the size of Earth's orbit, whereas Earth's volume is roughly 1 millionth (10 −6) that of the Sun. Jupiter, the largest planet, is 5.2 AU from the Sun and has a radius of 71,000 km (0.00047 AU; 44,000 mi), whereas the most distant planet, Neptune, is 30 AU ...
The star with the highest proper motion, [138] and the second-nearest star system to the Solar system. Has a planet, Barnard's Star b / Barnard b. [139] [105] Batsũ̀ (LHS 3844) 131,500 Has one confirmed exoplanet [140] Ross 248: 132,200 Tenth-nearest star system to the Solar System. [112] Gliese 1128: 132,200 [141] Alpha Mensae B 132,200 [142]
The observable universe contains as many as an estimated 2 trillion galaxies [36] [37] [38] and, overall, as many as an estimated 10 24 stars [39] [40] – more stars (and, potentially, Earth-like planets) than all the grains of beach sand on planet Earth. [41] [42] [43] Other estimates are in the hundreds of billions rather than trillions.
A star in this hypothetical state is called a "quark star" or more specifically a "strange star". The pulsar 3C58 has been suggested as a possible quark star. Most neutron stars are thought to hold a core of quark matter but this has proven difficult to determine observationally.
The list specifically excludes both white dwarfs – former stars that are now seen to be "dead" but radiating residual heat – and black holes – fragmentary remains of exploded stars which have gravitationally collapsed, even though accretion disks surrounding those black holes might generate heat or light exterior to the star's remains ...