Happy Birthday Sir Isaac Newton!
Oh, and merry Christmas and stuff.
Vulcan: The Hypothetical Planet
Mercury has a curiously eccentric orbit that early astronomers had difficulty plotting. Although the Sun has the biggest gravitational influence on it, every other object in the Universe has an influence on it too according to Newton’s laws of gravitation. These are faint in comparison to the Sun’s enormous pull, but astronomers still have to factor them into calculations of Mercury’s motions. But in the mid 1800s, after painstaking calculation involving every known factor, French astronomer Urbain Jean Joseph Leverrier found that something was still unaccounted for. Neptune had just been discovered and had solved the problems with Uranus’s orbit, so rather than question Newton, Leverrier proposed in 1860 that there must be an object inside of Mercury’s orbit—a new planet that would account for irregularities. Leverrier called it Vulcan, but there was one problem: no one had ever observed it. Over the following decades, reports trickled in about various objects inside Mercury’s orbits, some perhaps small planets and others perhaps groups of asteroids. But the data didn’t match up, and no solid, consistent evidence could be provided. Controversy sprung up in the astronomical community, and yet, if Newton was correct, then there had to be another force acting on Mercury. In 1915, Einstein’s Theory of General Relativity explained it. It turns out that Newtonian gravity breaks down under extreme conditions, and relativity can step in to make corrections. Being so close to the enormous force of the Sun is certainly an extreme condition—basically, the Sun’s massive energy acts as the extra force on Mercury. When Einstein explained Mercury’s motions without the need for Vulcan, this shadow of a planet shrunk into non-existence—but it wasn’t a terrible hypothesis. Leverrier simply made the best inference he could with the available data.
RYB Color Model
In his experiments with light, Isaac Newton recognized that colors could be created by mixing color primaries. In his Opticks, Newton published a color wheel to show the geometric relationship between these primaries. This chart was later confused and understood to apply to pigments as well, though Newton was also unaware of the differences between additive and subtractive color mixing.
The RYB model was used for printing, by Jacob Christoph Le Blon, as early as 1725.
In the 18th century, the RYB primary colors became the foundation of theories of color vision, as the fundamental sensory qualities that are blended in the perception of all physical colors and equally in the physical mixture of pigments or dyes. These theories were enhanced by 18th-century investigations of a variety of purely psychological color effects, in particular the contrast between “complementary” or opposing hues that are produced by color afterimages and in the contrasting shadows in colored light. These ideas and many personal color observations were summarized in two founding documents in color theory: the Theory of Colors (1810) by the German poet and government minister Johann Wolfgang von Goethe, and The Law of Simultaneous Color Contrast (1839) by the French industrial chemist Michel-Eugène Chevreul.
Subsequently, German and English scientists established in the late 19th century that color perception is best described in terms of a different set of primary colors – red, green and blue (RGB) modeled through the additive, rather than subtractive, mixture of three monochromatic lights.
Sorry - I’m a day late on this, but this book is one of the most significant works in the history of science, so I figured I’d still blog about it.
Anniversary of Sir Isaac Newton’s Principia Publication
Philosophiæ Naturalis Principia Mathematica, Latin for “Mathematical Principles of Natural Philosophy”, often referred to as simply the Principia, is a work in three books by Sir Isaac Newton, first published 5 July 1687. After annotating and correcting his personal copy of the first edition, Newton also published two further editions, in 1713 and 1726. The Principia states Newton’s laws of motion, forming the foundation of classical mechanics, also Newton’s law of universal gravitation, and a derivation of Kepler’s laws of planetary motion (which Kepler first obtained empirically). The Principia is “justly regarded as one of the most important works in the history of science”.
The French mathematical physicist Alexis Clairaut assessed it in 1747: “The famous book of mathematical Principles of natural Philosophy marked the epoch of a great revolution in physics. The method followed by its illustrious author Sir Newton … spread the light of mathematics on a science which up to then had remained in the darkness of conjectures and hypotheses.” A more recent assessment has been that while acceptance of Newton’s theories was not immediate, by the end of a century after publication in 1687, “no one could deny that” (out of the ‘Principia’) “a science had emerged that, at least in certain respects, so far exceeded anything that had ever gone before that it stood alone as the ultimate exemplar of science generally.”
In formulating his physical theories, Newton developed and used mathematical methods now included in the field of calculus. But the language of calculus as we know it was largely absent from the Principia; Newton gave many of his proofs in a geometric form of infinitesimal calculus, based on limits of ratios of vanishing small geometric quantities. In a revised conclusion to the Principia (see General Scholium), Newton used his expression that became famous, Hypotheses non fingo (“I contrive no hypotheses”).
Today is James Clerk Maxwell’s Birthday, Considered the Third Most Prominent Physicist in History
James Clerk Maxwell of Glenlair (13 June 1831 – 5 November 1879) was a Scottish physicist and mathematician. His most prominent achievement was formulating classical electromagnetic theory. This unites all previously unrelated observations, experiments, and equations of electricity, magnetism, and optics into a consistent theory. Maxwell’s equations demonstrate that electricity, magnetism and light are all manifestations of the same phenomenon, namely the electromagnetic field. Subsequently, all other classic laws or equations of these disciplines became simplified cases of Maxwell’s equations. Maxwell’s achievements concerning electromagnetism have been called the “second great unification in physics”, after the first one realised by Isaac Newton.
Maxwell demonstrated that electric and magnetic fields travel through space in the form of waves and at the constant speed of light. In 1865, Maxwell published A Dynamical Theory of the Electromagnetic Field. It was with this that he first proposed that light was in fact undulations in the same medium that is the cause of electric and magnetic phenomena. His work in producing a unified model of electromagnetism is one of the greatest advances in physics.
Maxwell also helped develop the Maxwell–Boltzmann distribution, which is a statistical means of describing aspects of the kinetic theory of gases. These two discoveries helped usher in the era of modern physics, laying the foundation for such fields as special relativity and quantum mechanics.
Maxwell is also known for presenting the first durable colour photograph in 1861 and for his foundational work on the rigidity of rod-and-joint frameworks like those in many bridges.
Maxwell is considered by many physicists to be the 19th-century scientist having the greatest influence on 20th-century physics. His contributions to the science are considered by many to be of the same magnitude as those of Isaac Newton and Albert Einstein. In the millennium poll—a survey of the 100 most prominent physicists—Maxwell was voted the third greatest physicist of all time, behind only Newton and Einstein. On the centennial of Maxwell’s birthday, Einstein himself described Maxwell’s work as the “most profound and the most fruitful that physics has experienced since the time of Newton.” Einstein kept a photograph of Maxwell on his study wall, alongside pictures of Michael Faraday and Newton.
Famous Astronomers | List of Great Scientists in Astronomy
Throughout human history, scientists have struggled to understand what they see in the universe. Famous astronomers — many of them great scientists who mastered many fields — explained the heavens with varying degrees of accuracy. Over the centuries, a geocentric view of the universe — with Earth at the center of everything — gave way to the proper understanding we have today of an expanding universe in which our galaxy is but one of billions. On this list are some of the most famous scientists from the early days of astronomy through the modern era, and a summary of some of their achievements.
When most people believed the world was flat, the notable Greek mathematician, astronomer and geographer Eratosthenes (276 BCE- 195 BCE) used the sun to measure the size of the round Earth. His measurement of 24,660 miles (39,690 kilometers) was only 211 miles (340 km) off the true measurement.
The ancient Greek astronomer and mathematician Claudius Ptolemy (AD 90- 168) set up a model of the solar system in which the sun, stars, and other planets revolved around Earth.
Persian astronomer Abd al-Rahman al-Sufi (903-986), known as Azophi to Westerners, made the first known observation of a group of stars outside of the Milky Way, the Andromeda galaxy.
In 16th century Poland, astronomer Nicolaus Copernicus (1473-1543) proposed a model of the solar system that involved the Earth revolving around the sun. The model wasn’t completely correct but it eventually changed the way many scientists viewed the solar system.
Using detailed measurements of the path of planets kept by Danish astronomer Tycho Brahe, Johannes Kepler (1571-1630) determined that planets traveled around the sun not in circles but in ellipses. In so doing, he calculated three laws involving the motions of planets that astronomers still use in calculations today.
Born in Italy, Galileo Galilei (1564-1642) is often credited with the creation of the optical telescope, though in truth he improved on existing models. The astronomer turned the new observational tool toward the heavens, where he discovered the four primary moons of Jupiter (now known as the Galilean moons), as well as the rings of Saturn. Though a model of the Earth circling the sun was first proposed by Copernicus, it took some time before it became widely accepted.
Dutch scientist Christiaan Huygens (1629-1695) proposed the earliest theory about the nature of light, a phenomena that puzzled scientists for hundreds of years. His improvements on the telescope allowed him to make the first observations of Saturn’s rings and to discover its moon, Titan.
Building on the work of those who had gone before him, English astronomer Sir Isaac Newton (1643-1727) is most famous for his work on forces, specifically gravity. He calculated three laws describing the motion of forces between objects, known today as Newton’s laws.
In the early 20th century, German physicist Albert Einstein (1879-1955) became of of the most famous scientists ever after proposing a new way of looking at the universe that went beyond current understanding. Einstein suggested that the laws of physics are the same throughout the universe, that the speed of light in a vacuum is constant, and that space and time are linked in an entity known as space-time, which is distorted by gravity.
At the same time Einstein was expanding man’s view of the universe, American astronomer Edwin Hubble (1899-1953) calculated that a small blob in the sky existed outside of the Milky Way. Prior to his observations, the discussion over the size of the universe was divided as to whether or not only a single galaxy existed. Hubble went on to determine that the universe itself was expanding, a calculation which later came to be known as Hubble’s law.
American astronomer Carl Sagan (1934-1996) may not have been a great scientists in comparison to some on this list, but he is one of the most famous astronomers. Sagan not only made important scientific studies in the fields of planetary science, he also managed to popularized astronomy more than any other individual. His charismatic teaching and boundless energy impacted people around the world as he broke down complicated subjects in a way that interested television viewers even as he educated them.
Stephen Hawking (born 1942) has made many significant insights into the field of cosmology. He proposed that, as the universe has a beginning, it will likely also end. He also suggested that it has no boundary or border. .
Other astronomers that achieved significant discoveries and are often mentioned among the greats:
Italian astronomer Giovanni Cassini (1625-1712) measured how long it took the planets Jupiter and Mars to rotate, as well as discovering four moons of Saturn and the gap in the planet’s rings. When NASA launched a satellite to orbit Saturn and its moons in 1997, it was fittingly dubbed Cassini.
Edmond Halley (1656-1742) was the British scientist who reviewed historical comet sightings and proposed that the comet which appeared in 1456, 1531, 1607, and 1682 were all the same, and would return in 1758.
French astronomer Charles Messier (1730-1817) composed a database of objects known at the time as “nebula,” which included 103 objects at its final publication, though additional objects were added based on his personal notes. Many of these objects are often listed with their catalog name, such as the Andromeda Galaxy, known as M31.
British astronomer William Herschel (1738-1822) cataloged over 2,500 deep sky objects. He also discovered Uranus and its two brightest moons, two of Saturn’s moons, and the Martian ice caps. William trained his sister, Caroline Herschel (1750-1848), in astronomy, and she became the first woman to discover a comet, identifying several over the course of her lifetime.
Henrietta Swann Leavitt (1868-1921)was one of several women working as a “computer” for Edwin Hubble at Harvard college, identifying images of variable stars on photographic plates. She discovered that the brightness of a special flashing star known as a Cepheid variable was related to how often it pulsed.
American astronomer Harlow Shapley (1885-1972) calculated the size of the Milky Way galaxy and general location of its center. He argued that the objects known as “nebula” lay within the galaxy, rather than outside of it, and in 1920 participated in the “Great Debate”.
Frank Drake (born 1930) is one of the pioneers in the search for extraterrestrial intelligence. He was one of the founders of the Search for Extraterrestrial Intelligence (SETI) and the deviser of the Drake equation, a mathematical equation used to estimate the number of extraterrestrial civilizations in the Milky Way galaxy able to be detected.
American astronomer William K. Hartmann (born 1939) put forth the most widely accepted theory on the formation of the moon in 1975. He proposed that, after a collision with a large body scooped, debris from the Earth coalesced into the moon.
—Nola Taylor Redd
there are some mother fuckers past and present that are so god damn plugged into this world it’s amazing
