Astronomy Picture of the Day |
APOD: 1998 September 20 - Isaac Newton Explains the Solar System
Explanation:
Sir Isaac Newton changed the world. Born in 1643,
Newton was only an
above-average student. But he went home from
Cambridge one summer in 1665,
thought a lot about the physical nature of the world, and came back two
years later with a revolutionary understanding of
mathematics,
gravitation, and
optics. A
Professor of his, upon understanding what
Newton had done,
resigned his own position at Cambridge so
Newton
could have it.
Newton's
calculus
provided a new mathematical framework for the rapid solution of
whole classes of physical problems.
Newton's
law of
gravitation explained
in one simple formula how apples fall and planets move.
Newton's insights
proved to be so overwhelmingly powerful he was the
first
scientist ever knighted.
APOD: 2000 January 8 - Albert Einstein Describes Space and Time
Explanation:
Albert Einstein
(1879-1955) is considered by many the greatest astrophysicist and
single most significant
Person of the 20th Century.
He is pictured here in the Swiss Patent Office where
he did much of his defining work.
Einstein's many visionary scientific contributions
include the equivalence of mass and energy (E=mc^2),
how the maximum speed limit of light affects measurements of time and space
(special relativity), and a more accurate
theory of gravity based on simple geometric concepts
(general relativity).
One reason
Einstein was awarded the 1921
Nobel Prize in Physics was to make the prize more prestigious.
APOD: 1998 October 27 - Henrietta Leavitt Calibrates the Stars
Explanation:
Humanity's understanding of the relative brightness and variability of stars
was revolutionized by the work of Henrietta Swan Leavitt (1868-1921).
Working at
Harvard College Observatory, Leavitt precisely
calibrated the photographic magnitudes of 47 stars to which all other
stars could be compared.
Leavitt discovered and cataloged over 1500
variable stars
in the nearby
Magellanic Clouds.
From this catalog, Leavitt discovered that brighter
Cepheid variable stars
take longer to vary, a fact used today to calibrate the
distance scale of our universe.
Authors & editors:
Robert
Nemiroff
(MTU)
& Jerry Bonnell (USRA)
NASA Technical Rep.:
Jay Norris.
Specific rights apply.
A service of:
LHEA at
NASA/
GSFC
&
Michigan Tech. U.