Testing Einstein’s theory with a new space probe to Mercury

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New Mercury Space Probe Will Put Einstein’s Gravity To The Test

orbit of Mercury, including effects from general relativity and other planets in the Solar System

The orbit of Mercury, including effects from general relativity and other planets in the Solar System. I’ve exaggerated the effect for easy viewing; in real life, the orbit is very nearly an ellipse. [Credit: Matthew R Francis]

For Forbes:

Despite the discovery of other galaxies, black holes and other marvelous astronomical bodies, we keep returning to the orbits of planets to understand gravity at its most basic. Partly that’s simplicity: We’re inside the Solar System and can make measurements without spending billions of dollars or building virtual observatories the size of the whole planet. But that doesn’t mean we’ve exhausted all the ways to learn about gravity from the dance of the planets.

In a new paper in Physical Review Letters, University of Florida physicist Clifford Will showed that the upcoming BepiColombo space probe may be able to test an aspect of Albert Einstein’s theory of gravity, general relativity, that’s been out of reach so far. This effect comes from the gravity of other planets in the Solar System, leading to a tiny shift in Mercury’s orbit. But small doesn’t mean unimportant: If general relativity needs to be modified on this tiny level, the BepiColombo probe may be able to spot that discrepancy.

[Read the rest at Forbes…]

Albert Einstein: Physicist and Social Justice Warrior

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From left: Former Vice-President Henry A. Wallace, Albert Einstein, Lewis Wallace, and Paul Robeson. Einstein had invited Wallace (who was running for President in 1948) and singer/actor/civil-rights activist Robeson to his house to discuss anti-lynching activism. Robeson asked Einstein to co-chair his  organization, American Crusade Against Lynching (ACAL). [Credit: Bettmann / Getty Images]

From left: Former Vice-President Henry A. Wallace, Albert Einstein, Lewis Wallace, and Paul Robeson. Einstein had invited Wallace (who was running for President in 1948) and singer/actor/civil-rights activist Robeson to his house to discuss anti-lynching activism. Robeson asked Einstein to co-chair his organization, American Crusade Against Lynching (ACAL). [Credit: Bettmann / Getty Images]

How Albert Einstein Used His Fame to Denounce American Racism

The world-renowned physicist was never one to just stick to the science

For Smithsonian Magazine:

By the spring of 1933, the most famous scientist in the world had become a refugee.

Einstein was a more fortunate refugee than most. By that time he was already a Nobel Prize winner and media celebrity, recognizable around the world. That fame made him a high-profile enemy for the new Nazi government in Germany, but it also guaranteed him safe places to go. Ultimately he ended up in America at the Institute for Advanced Study in Princeton, New Jersey, where he would spend the rest of his life.

Einstein saw racism as a fundamental stumbling block to freedom. In both his science and his politics, Einstein believed in the need for individual liberty: the ability to follow ideas and life paths without fear of oppression. And he knew from his experiences as a Jewish scientist in Germany how easily that freedom could be destroyed in the name of nationalism and patriotism. In a 1946 commencement speech at Lincoln University, the oldest black college in the U.S., Einstein decried American racism in no uncertain terms.

“There is separation of colored people from white people in the United States,” said the renowned physicist, using the common term in the day. “That separation is not a disease of colored people. It is a disease of white people. I do not intend to be quiet about it.” [Read the rest at Smithsonian Magazine]

My cats, Pascal and Harriet, with a few of my books that deal with the topic of relativity.

My cats, Pascal and Harriet, with a few of my books that deal with the topic of relativity.

Albert Einstein is many people’s archetype of the genius scientist, and his most famous equation is E = mc2. Or is it? When you look at Einstein’s published scientific papers over decades of work, he didn’t (usually) write the equation in that form. In fact, he pointed out that was an inaccurate form, since it’s a limiting case of a far more general principle. In my latest piece for Double X Science, I argued that the form of the equation is far less important than its meaning, and it doesn’t really matter if Einstein wrote E = mc2 or not.

When you study relativity, you find those equations are specific forms of more general expressions and concepts. To wit: The energy of a particle is only proportional to its mass if you take the measurement while moving at the same speed as the particle. Physical quantities in relativity are measured relative to their state of motion – hence the name. [Read more…]

Did Einstein ever write his most famous equation?