science

Find Your Address on Earth, 700 Million Years Ago

July 5, 2018 by Brian Ventrudo Filed Under: Science

The location of the author’s home in Maryland about 250 million years ago.

Like many important theories in science, plate tectonics, the concept that the Earth’s surface is like a cracked eggshell with each piece floating on a convective mantle of molten rock, was once considered a crackpot idea. But sometimes crackpot ideas are right. Plate tectonics now underpins all of geology, much like the Big Bang Theory is the foundation of astronomy and astrophysics.

The theory of plate tectonics was deduced in the mid-20th century by a handful of scientists and cartographers who wondered why, for example, the eastern coast of South America complemented so precisely the shape of the western coast of Africa, and why fossils of long-extinct animals were found scattered on different continents separated by wide oceans, and why volcanoes and earthquakes are far more common in some locations than others, and why fossilized marine creatures are sometimes found at the tops of mountains. Before plate tectonics, these observations were a mystery. After plate tectonics, they all started to make sense. [Read more…] about Find Your Address on Earth, 700 Million Years Ago

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The Mysterious Hiss from the Milky Way

July 22, 2017 by Brian Ventrudo Filed Under: Science

The northern summer Milky Way. The center of our galaxy lies just above the tree at lower center in this image. The Bell Labs radio engineer Karl Jansky discovered radio emissions from this location in the early 1930s. Image credit: Brian Ventrudo/CosmicPursuits.com.

In the early 1930′s, Bell Labs, the research division of AT&T, launched a project to use radio “short waves” to transmit telephone calls across the Atlantic. The technology to transmit signals via short waves was reasonably well understood. But engineers also needed to understand sources of noise that might interfere with radio communications signals. So the powers-that-were at Bell Labs tasked a young engineer to find sources of radio static that might interfere with transmissions. During his work, this young engineer, Karl Jansky, made an accidental discovery that revolutionized astronomy [Read more…] about The Mysterious Hiss from the Milky Way

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The Distances to the Galaxies

July 10, 2017 by Brian Ventrudo Filed Under: Science

Multiple images by NASA’s Hubble Space Telescope of the Cepheid variable star that in 1923 altered the course of modern astronomy. Called “V1″, it was first detected by Edwin Hubble with the 100” reflector at Mt. Wilson Observatory. Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)

In our previous stop on our tour of celestial objects of cosmological importance, we looked at a handful of galaxies measured by the early 20th-century astronomer Vesto Slipher. The former Indiana farm boy wrestled with a modestly endowed telescope and a 450-pound spectrometer to make an astonishing discovery. He found the ‘spiral nebulae’ like Andromeda (M31) and the Sombrero (M104) were moving away from us at astonishing speeds, up to 1000 km/s and far faster than any nearby stars. The speeds of these spiral assemblies strongly suggested they lay outside our own group of stars, and were perhaps separate galaxies in their own right far outside our own.

But in science, a strong suggestion is not proof.

In the first years of the 20th century, astronomers had no way of knowing for sure the distance to these spiral assemblies. Indeed, a hundred years ago, they only could estimate the distances to a handful of nearby stars. The true scale of even our own galaxy was a complete mystery. No one knew whether the Milky Way was all there was to the universe, and whether it was a hundred light years across, or a thousand, or a trillion. Never mind the distances to the mysterious ‘spiral nebulae’, which may simply have been nearby star systems in the process of formation.

The key to the distance to the spiral nebulae, which we now know to be separate galaxies, and to the universe itself, lay unexpectedly in a class of unassuming stars, many of which you can see from your backyard with a pair of binoculars or without any optics at all [Read more…] about The Distances to the Galaxies

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Geminid Meteor Shower 2015

December 11, 2015 by Brian Ventrudo Filed Under: Solar System, Stargazing

Meteors from the Geminid meteor shower (credit: Asim Patel)

As the days tick down to the December solstice, stargazers can engage in a little meteor watching as the Geminids meteor shower peaks during the nights of December 13-14, 2015. One of the best meteor showers of the year, the Geminids shows up to 100-150 meteors per hour in dark sky. This will be an excellent year because the waxing crescent Moon will set before the shower peaks [Read more…] about Geminid Meteor Shower 2015

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