A forgotten hero: Leavitt

Many of you must be familiar with the name Sir Edwin Hubble. He proved that milky way isn't the only galaxy in our universe. But he couldn't have done this all alone.

Henrietta Swan Leavitt who worked at Harvard college observatory' played a major role in his discoveries.

Yet she is so unknown.

Leavitt discovered that there is a regular relationship between the brightness of Cepheid stars and the period of their variation. If one could determine the distance of a single Cepheid star with a particular period then measuring the brightness of other Cepheid stars with same period could tell us about their distance.

Cepheid variable stars are stars whose brightness varies over some regular period.

A question arises "How can one determine the distance of a star using its brightness?"

Observed brightness of a star is measured by the amount of energy absorbed by a telescope. It is inversely proportional to the square of the distance of star.

Relation between Flux and distance

Measuring distances was a complicated task in astronomy but Leavitt's relation revolutionized this field. Using this relation Hubble was able to measure the distances to few stars and nebulae and proved that these stars and nebulae are too far away so they cannot be a part of milky way galaxy and thus proved that milky way isn't the only galaxy.

In 1924, the Royal Swedish house had begun the paperwork to nominate Leavitt for Nobel Prize but she died from Cancer in 1921. Thus she remains forgotten.