The sun is always shining on Joan Feynman

“I knew the names of the planets in order before I went to kindergarten,” Joan Feynman, the younger sister of the famous physicist, told me. “My father was delighted by science. My brother, of course, was Richard Feynman—gifted as hell. When I was about three or four, he taught me to add numbers. I’d add them and if I got them right, he’d give me a reward. The reward was allowing me to pull his hair. As soon as I pulled his hair he’d make a terrible face.”

Left: Joan Feynman. Credit: NASA. Right: Richard Feynman. Credit: The National Nanotechnology Initiative

Left: Joan Feynman. Credit: NASA. Right: Richard Feynman. Credit: The National Nanotechnology Initiative

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The Northern Lights – A Magic Light Display

For thousands of years people in the northern part of the world have marveled at the spectacular and fearful displays that occasionally light up the night sky. The Norwegian scientist Kristian Birkeland, 1867-1917 was the first explain the real cause – that particles from the Sun were sparking the Northern Lights. To prove his theory—which is still valid today–he built his own small world in a glass box, electrified his model of Earth with its own magnetic field and showed how particles from the Sun could ignite auroras. The particles were captured by the Earth’s magnetic field and channeled down toward the Polar Regions.

Kristian Birkeland with his Terella experiment. The metal sphere was his model Earth, while the vacuum glass container was space. When Birkeland sent particles toward the sphere, the Polar Regions glowed.  Credit: University of Oslo.

Kristian Birkeland with his Terella experiment. The metal sphere was his model Earth, while the vacuum glass container was space. When Birkeland sent particles toward the sphere, the Polar Regions glowed. Credit: University of Oslo.

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Variations in starlight tell us about faraway planets

Variations in the brightness and color of light from stars provide the key to the detection and characterization of planets orbiting other stars. As a planet crosses the disk of its star, called a transit, it causes a tiny reduction in the amount of light from the star. This tells us the size of the planet relative to the size of the star and the time between transits gives us the planet’s orbital period.

By measuring the color of the light, called a spectrum from the star and measuring pulsations of its brightness caused by waves traveling over the surface and inside the star, we can determine its size, age, temperature, and mass. From the star properties and the distance of the planet from the star we can make an estimate of the radiant heat flux at the planet.  Determining the properties of a star is key to understanding the properties of the planet. We like to say that you know the planet only as well as you know the star.

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Artist conception of planet Kepler 10b. Kepler-10b is a planet 1.4 times the size of the Earth with an orbital period of 0.84 days. Its temperature of 2169 °C exceeds that of molten iron. Credit: NASA.

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Lasers on the Red Planet

Our neighboring planet, Mars, may be responsible for the literary genre of science fiction. It was after the supposed discovery of “canals” on Mars, popularized in the late 19th century first by Giovanni Schiaparelli in Europe and then by Percival Lowell in the US, that stories of aliens equipped with light sabers became popular.

In the last two decades we humans have turned the tables on the Martians with the use of lasers to explore the red planet. While the lasers used for exploration are not the heat rays envisioned in H.G. Wells’ War of the Worlds, these light beams have been used in a variety of ways.

Artist conception of the ChemCam instrument performing laser analysis of a rock outcrop on Mars. ChemCam can analyze targets at distances up to 7 m. Credit: J.-L. Lacour

Artist conception of the ChemCam instrument performing laser analysis of a rock outcrop on Mars. ChemCam can analyze targets at distances up to 7 m. Credit: J.-L. Lacour

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Fifty years of cosmic microwave background

Discovered in 1965, the cosmic microwave background (CMB) is the most ancient light record in the history of the Universe. Despite being detected as a “noise” across the sky, it did not take long for scientists to realise that this radiation is an incredibly rich source of information about the history of the cosmos, setting them on a search for more and more details in this early cosmic signal.

An artistic view of the evolution of the Universe, highlighting the phenomena that gave rise to the Cosmic Microwave Background. Credit: ESA

An artistic view of the evolution of the Universe, highlighting the phenomena that gave rise to the Cosmic Microwave Background. Credit: ESA

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