It's about 0.000000010 times as fast as The Speed of Light.
In other words, 0.0084 mach is 0.000000009289919870 times the speed of The Speed of Light, and the speed of The Speed of Light is 107,643,555 times that amount.(C) (in a vacuum)
The speed of light (and all other electromagnetic radiation) in a perfect vacuum is known as "c" and measures exactly 904,205.8620 mach, per the formal definition of the meter. While visible light travels close to this speed in air, it slows to 602,803.9080 mach when passing through the glass of a typical window.
It's about one-thirty-five-thousandth as fast as a bolt of Lightning.
In other words, the speed of a bolt of Lightning is 36,000 times 0.0084 mach.(atmospheric electrical discharge)
A bolt of lightning can travel at up to 290 mach when arcing from the atmosphere to the Earth. An estimated 280 million lightning strikes strikes occur each year.
It's about one-fifteen-thousandth as fast as a Meteor.
In other words, the speed of a Meteor is 15,000 times 0.0084 mach.(formally Meteoroid or meteorite, depending on the context; a.k.a. "shooting star", a.k.a. "falling star")
Small meteoroids enter the Earth's atmosphere at speeds between 34 mach and 220 mach, depending on their size. The fireball effect, known as ablation, ceases once the atmosphere has slowed the meteoroid to a velocity of about 8.40 mach.
It's about one-three-thousandth as fast as The Space Shuttle.
In other words, 0.0084 mach is 0.00035966 times the speed of The Space Shuttle, and the speed of The Space Shuttle is 2,780.40 times that amount.(Orbiter vehicle velocity)
The space shuttle orbits at a speed of 23.3560 mach. During liftoff, the space shuttle accelerates to orbital speed in 8.5 minutes, consuming over 1.59 million kg (3.51 million lbs) of propellant in the process.
It's about one-three-hundred-fiftieth as fast as a Bullet (Rifle).
In other words, 0.0084 mach is 0.00304 times the speed of a Bullet (Rifle), and the speed of a Bullet (Rifle) is 329 times that amount.(5.56 x 45 mm, a.k.a. 5.56 NATO)
A 5.56 x 45 mm cartridge is fired at a velocity of 2.760 mach. As the NATO rifle cartridge, it is used by the military forces of more than thirty-one countries, including use in the M16 series, M4 Carbine, HK-416, and M249 Squad automatic weapons used by the United States armed forces.
It's about one-two-hundred-fiftieth as fast as a Jet Fighter.
It's about one-one-hundred-fiftieth as fast as a Bullet (Handgun).
In other words, 0.0084 mach is 0.00725 times the speed of a Bullet (Handgun), and the speed of a Bullet (Handgun) is 138 times that amount.(for .40 Smith & Wesson 135 grain Sierra JHP, VV 3N37 powder, Fed. 100 primer, Remington case) (muzzle velocity)
A 0.40 caliber Smith & Wesson bullet has a muzzle a velocity of 1.160 mach. This type of ammunition has been the standard issue round of the United States Federal Bureau of Investigation (FBI) since 1990.