Astrophysics (Index)About


(second inner-most planet in the solar system)

Venus is the second solar system planet from the Sun. By many characteristics it is the most-Earth-like solar system planet, but with some distinct differences as well. Characteristics:

It has no moons. It is a rocky planet with an extremely dense atmosphere (91 atm) with more than 95% carbon dioxide, but has a minimal magnetic field. Its rotation is strikingly slow and retrograde (opposite of its orbit; among the other solar system planets, only Uranus's rotation is retrograde). Its surface temperature is 737 K, far hotter than any other solar system planet including Mercury, apparently the end effect of a runaway greenhouse effect, consistent with the striking amount of a greenhouse gas (carbon dioxide) in its atmosphere.

There is some thought that Venus formerly had liquid water on the surface, potentially for billions of years, presumably long enough for life to take hold and evolve, before the extreme greenhouse effect took hold.

There has been relatively little exploration of Venus (as compared to Mars), due to the extreme challenge of operating equipment at its temperature. The Soviet Union launched the majority of missions specifically to study Venus; NASA launched a few and also has had a number of incidental flybys allowing for some observation, in part to use Venus for gravity assists in flights to other solar system destinations.

(planet,solar system)
Further reading:
/Lookback Years

Referenced by pages:
apparent magnitude (m)
astronomical symbol
atmospheric tide
carbonate-silicate cycle
carbon dioxide (CO2)
Earth analog
equilibrium temperature (Teq)
gravity assist
greenhouse effect
habitable zone (HZ)
late heavy bombardment (LHB)
magnetic field
moment of inertia factor
Parker Solar Probe (PSP)
point source
precession of the equinoxes
Pioneer Venus Orbiter (PVO)
retrograde orbit
rocky planet
rotation period
supercritical fluid (SCF)
Shapiro delay
solar day
superrotating wind
tidal locking
Titius-Bode law
transiting planet