Blue Dog's eyes

Cosas con las que me encuentro

How Do We Know the Earth Orbits the Sun? 

"There was a recent news item about Star Trek’s Kate Mulgrew in a geocentric movie. The geocentric model states that the Sun and the planets move around the Earth instead of the heliocentric model with the Sun in the center. That’s just silly, right? Obviously the Earth orbits the Sun.

Sure, the textbooks all say that the solar system is heliocentric. But how do we know that? More importantly, how can YOU tell which is the better model?

A Case For the Geocentric Model
The geocentric model is no more crazy than saying that a tennis ball is made of protons, neutrons and electrons. Sure, we all (most of us) believe there are these particles like electrons – but how do normal humans know this?


In fact, the evidence in our everyday lives doesn’t make it obvious that there are protons and electrons (yes, you could argue the mere fact of things like computers says these have to exist). The same is true for the heliocentric model…

How Can You Tell the Earth Orbits the Sun?

No one likes to just trust the textbook. You don’t have to. Here are some things you can do to determine for yourself what orbits what.

Phases of Venus. The next time Venus is visible in the sky, take a look at it with some binoculars. It will probably look something like this.


That’s not the best picture, but the only one I could find. The brighter object is Venus. If the image had a better resolution, you would be able to see that Venus shows the same kind of phase that we see with the moon. What does this mean? It means two things.

First, We can see Venus because it reflects light from the Sun. Second, as the phases change, Venus is sometimes closer to us that the Sun and sometimes farther away. You would see a “full phase” Venus when it is on the other side of the Sun. How can both Venus and the Sun orbit the Earth but also have Venus move farther away?

Oh, this is something that Galileo saw with his telescope…”


(by Kate Beaton)

Read all at


Ernest Everett Just (August 14, 1883 – October 27, 1941) was a pioneering African-American biologist, academic and science writer.

Just’s primary legacy is his recognition of the fundamental role of the cell surface in the development of organisms. In his work within marine biology, cytology and parthenogenesis, he advocated the study of whole cells under normal conditions, rather than simply breaking them apart in a laboratory setting.

Born into a poor family in Charleston, South Carolina, Just overcame barriers of race and poverty to be admitted into Kimball Union Academy in New Hampshire, where he finished a four-year high school curriculum in only three years and graduated valedictorian. He then won a scholarship to Dartmouth College and again excelled scholastically. He graduated with a B.A. degree in 1907, having majored in biology and minored in Greek and history, and was the only magna cum laude student in his class.


After graduating, Just took a teaching position at Howard University in Washington, D.C., and, beginning in 1909, spent 20 summers at the Marine Biological Laboratory in Woods Hole, Massachusetts. Through the meticulous research he conducted there, Just became known as a leading authority on the embryology of marine animals. In 1915, he was the first recipient of the National Association for the Advancement of Colored People’s (NAACP) Spingarn Medal, awarded to men and women of African descent who have made outstanding achievements in their fields.

Taking a temporary leave from his position at Howard, Just entered the University of Chicago and, in 1916, was the first African American to receive a Ph.D. degree in experimental embryology, again graduating magna cum laude.


Despite his increasingly distinguished career, his significant contributions in the area of the physiology of development, and the numerous papers he began to publish on fertilization and experimental parthenogenesis, Just struggled against racial barriers. Starting in 1929, he spent most of his time conducting research in Germany, France, and Italy. Europe remained the center of his activity until the German occupation of France in 1940.

At the outbreak of World War II, Ernest Just was working at the Station Biologique in Roscoff, France, researching the paper that would become Unsolved Problems of General Biology. Although the French government requested foreigners to evacuate the country, Just remained to complete his work. In 1940, Germany invaded France and Just was briefly imprisoned in a prisoner-of-war camp.

He was rescued by the U.S. State Department and returned to his home country in September 1940. However, Just had been very ill for months prior to his encampment and his condition deteriorated in prison and on the journey back to the U.S. In the fall of 1941, he was diagnosed with pancreatic cancer, and died shortly thereafter



Further reading Black Apollo of Science: The Life of Ernest Everett Just


An Electro-Photographic Investigation of Consecutive Phases of Animal Movements (1872 - 1885)  Eadweard Muybridge (1830–1904)

"In the 1880s, the University of Pennsylvania sponsored Muybridge’s research using banks of cameras to photograph people in a studio, and animals from the Philadelphia Zoo to study their movement.

The human models, either entirely nude or very lightly clothed, were photographed against a measured grid background in a variety of action sequences, including walking up or down stairs, hammering on an anvil, carrying buckets of water, or throwing water over one another.

Muybridge produced sequences showing farm, industrial, construction, and household work, military maneuvers, and everyday activities. He also photographed athletic activities such as baseball, cricket, boxing, wrestling, discus throwing, and a ballet dancer performing.

Showing a single-minded dedication to scientific accuracy and artistic composition, Muybridge himself posed nude for some of the photographic sequences, such as one showing him swinging a miner’s pick”