How much light does that exposure let in?

Every photographic control moves in stops, and a stop is always exactly a doubling of light.

Shutter speed Unit

Almost exactly 1/125 s

0.008 s is longer than 3 of the 8 references on this page.

Reference figures are measurements and are rounded; the unit conversion behind them is exact.

Every reference on this page, with its size and its ratio to your number
Reference	Size	Yours ÷ theirs	Note
1/8000 s	0.000125 s	64×
1/1000 s	0.001 s	8×	Freezes a running person
1/250 s	0.004 s	2×
1/125 s	0.008 s	1×	The old hand-held rule
1/30 s	0.0333 s	0.24×
1/4 s	0.25 s	1/31.3
1 s	1 s	1/125
30 s	30 s	1/3,750	The longest most cameras offer directly

Each step in the standard shutter series doubles the light — one stop. Aperture and ISO use the same currency, which is what makes the exposure triangle work.
The old rule of thumb was that hand-held shutter speed should be at least one over the focal length. Stabilisation has bought about four stops on that.

Frequently asked

A doubling or halving of light. One stop can be bought with shutter speed, aperture area or ISO, and the three are interchangeable for exposure.

Because aperture area goes as the square of the diameter, so each full stop multiplies the f-number by the square root of two.