BellaOnline Forums Education Astronomy It happened on July 4th

Born on the Fourth of July 1868, Henrietta Leavitt, working at the Harvard College Observatory, made one of the most important discoveries of 20th century astronomy. Previously, astronomers could only measure distances up to 100 light years, but her work extended that to 10 million light years.

Henrietta Swan Leavitt

In the early 20th century an astronomer made a revolutionary discovery. Yet her life left almost no footprints on history. "Miss Leavitt's Stars" contrasts the solidity of her professional accomplishment with the butterfly touch of her life. Miss Leavitt isn't even the star of her own biography.

Miss Leavitt's Stars - book review

What links the USA's Independence Day holiday, the Crab Nebula and NASA's Deep Impact spacecraft? What links the American War of Independence with the planet Uranus? And what is the Fireworks Galaxy? Here's the story.

Cosmic 4th of July

Chinese astronomers first recorded a "guest star" - a supernova, in this case - on July 4, 1054. The remnant of this might explosion is Messier 1, the Crab Nebula.

Messier's catalog of nebulous objects begins with M1 the Crab Nebula. In 18th-century telescopes it was just a fuzzy patch, yet imaged by the Hubble Space Telescope, it's fascinating and intricate. But what is it? Why is it called the Crab Nebula? And what amazing secret does it hide?

M1 Crab Nebula

Here's Pathfinder's view on Mars. It landed on July 4, 1997, and I'm pretty sure NASA set off some extra fireworks in celebration. The lander was given a new name: Carl Sagan Memorial Station. Pathfinder's rover Sojourner was the first successful Mars rover.

Mona, you always write about such interesting people. Thank you.

And thank you, Angie, for your encouraging comments.

By UTC (Coordinated Universal Time) NASA's Juno mission was inserted into its orbit around Jupiter on July 5, 2016. But in USA time zones it happened on July 4th.

Juno's close-up images of Jupiter have grabbed the attention of scientists, but have also, with color enhancement, provided for everyone exquisite works of art. Have a look at the swirling clouds of Jupiter's northern hemisphere.

amazing.

Hello there,

I have to agree with Angie and everyone else - Mona, you should be knighted for your work on Bellaonline - I am a lurker for the most part but I have gained so much by having subscribed to your site. I have to put on my thinking cap when reading but enjoy trying to 'see' what's out there, though there are times when my mind is overwhelmed by the beauty and size and possibility of it all.

In a world that is insane in many areas, there is always something positive to understand about humanity in the work that astronomers do.

Thank you Mona.