Torr Specs by Vacuum Conditions and NASA Nonsense

No Space Suit Made by NASA Can Withstand The Vacuum of Outer Space

What is a Torr?

The torr (symbol: Torr) is a non-SI unit of pressure defined as 1/760 of an atmosphere. It was named after Evangelista Torricelli, an Italian physicist and mathematician who discovered the principle of the barometer in 1644.

Torricelli attracted considerable attention when he demonstrated the first mercury barometer to the general public. He is credited with giving the first modern explanation of atmospheric pressure. Scientists at the time were familiar with small fluctuations in height that occurred in barometers. When these fluctuations were explained as a manifestation of changes in atmospheric pressure, the science of meteorology was born.

Over time, 760 millimeters of mercury came to be regarded as the “standard” atmospheric pressure. The unit of barometric pressure (one millimeter of mercury, also written as 1 mm Hg) was named in honor of Torricelli.

In 1954, the definition of atmosphere was revised by the 10e Conférence Générale des Poids et Mesures (10th CGPM) to the currently accepted definition: one atmosphere is equal to 101325 pascals. The torr was then re-defined as 1/760 of one atmosphere. This change in the definition of “torr” has been a source of confusion ever since.                                                             

Torr Specs by Vacuum Conditions

Vacuum quality is subdivided into ranges according to the technology required to achieve it or measure it. These ranges do not have universally agreed definitions (hence the gaps below), but a typical distribution is as follows:

Atmospheric Pressure             760 Torr                          101 kPa

Low Vacuum                      760 to 25 Torr                    100 to 3 kPa

Medium Vacuum           25 to 1×10-3 Torr                   3 kPa to 100 mPa

High Vacuum            1×10-3 to 1×10-9 Torr                100 mPa to 1 µPa

Ultra-High Vacuum     1×10-9 to 1×10-12 Torr          100 nPa to 100 pPa

Extremely High Vacuum      1×10-12 Torr                    100 pPa

Outer Space              1×10-6 to <3×10-17 Torr            100 µPa to <3fPa

Perfect Vacuum                  0 Torr 0 Pa

Low vacuum, also called rough vacuum or coarse vacuum, is vacuum that can be achieved or measured with rudimentary equipment such as a vacuum cleaner and a liquid column manometer.

Medium vacuum is vacuum that can be achieved with a single pump but is too low to measure with a liquid or mechanical manometer. It can be measured with a McLeod gauge, thermal gauge or a capacitive gauge.

High vacuum is vacuum where the MFP of residual gases is longer than the size of the chamber or of the object under test. High vacuum usually requires multi-stage pumping and ion gauge measurement. Some texts differentiate between high vacuum and very high vacuum.

Ultra-high vacuum requires baking the chamber to remove trace gases, and other special procedures.

Deep space is generally much emptier than any artificial vacuum that we can create.

Perfect vacuum is an ideal state that cannot be obtained in a laboratory, nor even in outer space.

Vacuum Examples

Vacuum Cleaner                      approximately 80 kPa                       (600 Torr)

Liquid Ring Vacuum Pump     approximately 3.2 kPa                      (24 Torr)

Freeze Drying                              100 to 10 Pa                              (1 to 0.1 Torr)

Rotary Vane Pump                  100 Pa to 100 mPa                     (1 Torr to 10−3 Torr)

Incandescent Light Bulb               10 to 1 Pa                               (0.1 to 0.01 Torr)

Thermos Bottle                            1 to 0.1 Pa                             (10−2 to 10−3 Torr)

Near Earth Outer Space             approx.. 100 µPa                         (10−6 Torr)

Cryopumped MBE Cham.         100 nPa to 1 nPa                     (10−9 Torr to 10−11 Torr)

Pressure on the Moon             approx.. 1 nPa                                (10−11 Torr)

Interstellar Space                  approximately 1 fPa                         (10−17 Torr                            

ImpossiBALL Jupiter

Jupiter is said to be a giant ball of gas, with no solid surface. It is allegedly composed of the very light gases, hydrogen and helium. Because of dispersion, Entropy and the Second Law of Thermodynamics, we know gas will always disperse to fill any vacuum. Jupiter cannot be a ball of gas and still remain intact against the near perfect vacuum of Outer Space unless the entire surface of Jupiter has a hard shell container. Jupiter is not a ball of gas.