They mean the differential is 1atm in space. Because it's 1atm of pressure within earth's atmosphere at sea level, but is nearly 0atm in the vacuum of space, so the pressure differential is 1atm.

Meanwhile, pressure increases by 1atm roughly every 10m of depth in the ocean. The average ocean depth is 3700m, so a pressure of about 370atm. The pressure differential between the surface and that is 369atm, far larger than the 1atm differential between the surface and the vacuum of space.

jkmoulet1_iy2utag wroteReply to comment by

bak3donh1ghinTIL More than 80 percent of the ocean has never been mapped, explored, or even seen by humans and as a result, we know more about the surface of Mars than Earthby[deleted]They mean the differential is 1atm in space. Because it's 1atm of pressure within earth's atmosphere at sea level, but is nearly 0atm in the vacuum of space, so the pressure differential is 1atm.

Meanwhile, pressure increases by 1atm roughly every 10m of depth in the ocean. The average ocean depth is 3700m, so a pressure of about 370atm. The pressure differential between the surface and that is 369atm, far larger than the 1atm differential between the surface and the vacuum of space.