Gravity and Pressure

[Dmitry67]

So, ideal gas under a high pressure produces more gravity because of the pressure components in the stress-energy tensor.

However, high pressure of an ideal gas can be explained as just moving particles. These particles can be quite big and heavy - for example, stars in a galaxy.

I wonder how these views might be consistent. Why moving particles generate more gravity? just because their relativistic mass is bigger?

[Naty1]

The stress energy tensor reflects mass,energy and pressure as sources of gravity....and negative pressure as a cause of repulsive gravity....so it's not as simple as the relativistic energy of moving particles....