Spectroscopy — the use of light from a distant object to work out the object is made of — could be the single-most powerful tool astronomers use, says Professor Fred Watson from the Australian Astronomical Observatory. ... "It lets you see the chemicals being absorbed or emitted by the light source.
1 pound ≈ 0.4536 kg
170 pounds ≈ 170 * 0.4536 kg
≈ 77.112 kg
