Venus may have been once covered with vast oceans of carbon dioxide (CO2) fluid, suggest researchers.

Scientists often describe Venus as the twin of Earth as the mass, size and distance is very similar to that of the Earth. However, Earth supports life and Venus does not.

Researchers at the Cornell University, Ithaca, New York, suggest that even though Venus is extremely hot and dry currently, the planet may have had oceans like Earth. Previous studies have indicated that in the past the atmosphere of Venus had enough water to entirely cover the planet's surface by about 80 feet, or 25 meters deep, if it was to fall down on the surface.

However, Dima Bolmatov, a theoretical physicist at Cornell University, who is also the lead author of the study, reveals that instead of water, Venus may have had oceans of CO2 fluid. Bolmatov suggests that CO2 is extremely common on Venus and comprises the majority of the planet's atmosphere.

"Presently, the atmosphere of Venus is mostly carbon dioxide, 96.5 percent by volume," says Bolmatov.

Researchers suggest that CO2 can actually exist in gas, liquid or solid form. However, CO2 can achieve a "supercritical" state after passing a critical point of combined pressure and temperature. A supercritical CO2 fluid can flow like gas and dissolve materials like liquid.

Bolmatov examined the possible effects of supercritical CO2 on Venus by understanding the properties related to supercritical matter.

Scientists suggest that supercritical fluids' physical properties altered with temperature and pressure. However, molecular activity examined in computer simulations revealed that supercritical matter can shift intensely from gas-like to liquid-like properties.

The atmospheric pressure on Venus' surface is currently over 90 times in comparison to the Earth. Scientists believe that the surface pressure of Venus may have been greater in the past, which would have lasted for 100 to 200 million years. Such conditions on the planet may have formed supercritical CO2 that had liquid-like properties.

Bolmatov says that his team will conduct further experiments to identify the shift from gas-like to liquid-like properties in supercritical CO2.

The findings of the study were published earlier this year in the Journal of Physical Chemistry Letters.