Edwin Hubble was born in 1889. He showed that spiral nebulae were separate galaxies. Using data collected with Humason & by Slipher, he established a linear relationship between a galaxy’s distance & recession velocity — later interpeted as evidence of an expanding universe.

So if you know or have a curious kid with questions about black holes, or if you ARE a curious kid with questions about black holes, check it out.

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I'm on "The Show About Science" talking to 8 year old host Nate Butkus about black holes.

Friends, never pass up a chance to explain to a second grader how extreme tidal forces could turn them into spaghetti.


Jansky built a directional antenna to pinpoint the source of radio static that was interfering with phone calls. He referred to the antenna as his "merry-go-round" – it rotated on a set of wheel from a Model-T Ford.
Image: Bell Telephone Laboratories

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The physicist Karl Jansky was born in 1905. While searching for the source of radio hiss that interfered with transatlantic phone calls for Bell Labs, he discovered that astrophysical objects emit radio waves. It was the birth of radio astronomy.

The National Aeronautics and Space Administration began operations in 1958. Congress had passed the act creating it on July 16 of that year, with President Eisenhower signing it a few weeks later.

Happy 60th birthday, NASA!

Images: NASA / Project Apollo Archive (flickr.com/photos/projectapoll)

It’s the formula we all know: E = mc².

Einstein submits "Does the Inertia of a Body Depend Upon Its Energy-Content?" to Annalen der Physik in 1905. It is his second special relativity manuscript, the one in which he proposes the equivalence of mass and energy. His first special relativity paper had appeared in print the day before.

An English translation: fourmilab.ch/etexts/einstein/E

Albert Einstein wrote an excited postcard to his mother in 1919. It read "Joyous news today. H.A. Lorentz telegraphed that the English expeditions have actually measured the deflection of starlight from the Sun."

Hermann Minkowski addressed the 80th Assembly of German Natural Scientists and Physicians in 1908, presenting his radical reformulation of Einstein's theory of special relativity in terms of a four-dimensional spacetime.

So yes, by all means, if you are a billionaire who can make it happen, please send artists to the moon. Send poets, painters, and writers. Send folks who’ll see the moon growing large, the Earth small and flawless, and find perspectives that frame our place in the vast, lonesome cosmos.

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Twelve-and-a-half years passed between this view of the Earth and Moon in a single frame, and Sagan and colleagues thinking to turn Voyager 1’s cameras back towards Earth to capture a solar system mosaic that included the Pale Blue Dot photo.
Images: NASA / JPL

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The Voyager 1 spacecraft, 7.25 million miles away and speeding towards Jupiter, looked homeward in 1977 and captured the first picture of the whole Earth and Moon together in the same frame.
Image: NASA / JPL

Friends, @AstroKatie and I wrote a paper!

We argue that if extra dimensions exist then they must be pretty small, otherwise collisions between ultra-high energy cosmic rays could form tiny black holes whose evaporation might set off a catastrophic vaccum decay.


FEMA uses the status of Waffle Houses as a measure of a region’s resiliency to and recovery from natural disaster. This is great on so many levels, and also makes me really crave Waffle House.

The astronomer Mary Watson Whitney, known for work on variable stars and using photographic plates to make astronomical measurements, was born in 1847.

Whitney was one of Maria Mitchell’s first students, and succeeded her as director of Vassar's Observatory and chair of its astronomy department. She served for 22 years, during which time the department published over 100 papers in major journals. Near the end of her tenure there were 160 students enrolled in the program.

Image: Vassar

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