<P> Unlike Earth , Venus lacks a magnetic field . Its ionosphere separates the atmosphere from outer space and the solar wind . This ionised layer excludes the solar magnetic field , giving Venus a distinct magnetic environment . This is considered Venus 's induced magnetosphere . Lighter gases , including water vapour , are continuously blown away by the solar wind through the induced magnetotail . It is speculated that the atmosphere of Venus up to around 4 billion years ago was more like that of the Earth with liquid water on the surface . A runaway greenhouse effect may have been caused by the evaporation of the surface water and subsequent rise of the levels of other greenhouse gases . </P>
<P> Unlike Earth , Venus lacks a magnetic field . Its ionosphere separates the atmosphere from outer space and the solar wind . This ionised layer excludes the solar magnetic field , giving Venus a distinct magnetic environment . This is considered Venus 's induced magnetosphere . Lighter gases , including water vapour , are continuously blown away by the solar wind through the induced magnetotail . It is speculated that the atmosphere of Venus up to around 4 billion years ago was more like that of the Earth with liquid water on the surface . A runaway greenhouse effect may have been caused by the evaporation of the surface water and subsequent rise of the levels of other greenhouse gases . </P>
venus 's atmosphere has much more carbon dioxide than earth 's because
venus 's atmosphere has much more carbon dioxide than earth 's because
A runaway greenhouse effect
A runaway greenhouse effect