Voyager 1’s outbound trajectory took it by Jupiter in 1979, then past Saturn the next year.

This time lapse of the Jupiter approach consists of 66 frames, take once per Jovian day. Look carefully for moons darting past, shadows flickering across the face of the planet.

Credit: NASA/JPL

The Voyager 1 space probe was launched from Cape Canaveral #OTD in 1977, a few weeks after Voyager 2.

Now it's the most distant human-made object – about 14.96 billion miles from Earth, racing away from us at 38,000 miles per hour with respect to the Sun.

Images: NASA/KSC/JPL

@androidarts @nyrath I was addicted to that game

@cybeej Hahaha. The poll of a man with 25” counters trying to buy a new stove.

@llewelly idk, just assumed it was one of the vomit comets!

(Imo, “civilian” in this context refers to folks without a military background or similar.)

Teacher and astronaut Christa McAuliffe was born #OTD in 1948. Selected as the first American civilian to go into space, she was one of the seven crew members onboard the Space Shuttle Challenger when it was lost in 1986.

Image: NASA

@thomasfuchs I mean look how compact, you could put one of those in the same room as your computer!

Great summary.

☝️ Today a physics major came to class wearing an "Unknown Pleasures" shirt and I got to tell her about the image on the album cover.

Sooner or later one of these will get us, and a lot of our infrastructure won't be ready. Maybe we'll get lucky, or maybe it will be a disaster on a different scale than what we are familiar with.

Anyway, have a great weekend!

"I was suddenly surprised at the appearance of a very brilliant star of light, much brighter than the sun's surface, most dazzling to the protected eye..."

Here is the note by Hodgson recounting his observations.

https://academic.oup.com/mnras/article/20/1/15/983490?login=false

Here's Phil Plait (@badastro) writing about our 2012 near-miss, a few years after it happened.

https://slate.com/technology/2014/08/solar-storm-a-massive-2012-cme-just-missed-the-earth.html

On the other hand, as global disasters go it will be one of the prettier ones.

Aurora will be visible at every latitude. They will be dazzling and bright enough for you to read a book by; birds will think day is here.

@_thegeoff I really don't know enough to say. But in places like the eastern US I assume we're still too susceptible to single points of failure.

Telecoms will go down hard, and there’s a good chance your power grid will collapse.

Estimates in 2008 suggested as many as 130 million people in the US might experience power loss. In the most dire scenarios, full recovery was measured in years rather than months.

https://nap.nationalacademies.org/catalog/12507/severe-space-weather-events-understanding-societal-and-economic-impacts-a

Image: NAS

It's estimated that "Carrington event" solar storms happen every 150 years or so.

At some point it will happen again, and it won’t miss Earth. And since the infrastructure we now rely on is much more susceptible than it was in 1889, the result will be a true large-scale disaster.

The National Academy of Sciences reported in 2014 that the economic impact of a modern-day Carrington Event could top $2 trillion.
https://science.nasa.gov/science-news/science-at-nasa/2014/23jul_superstorm/

The solar storm that followed was one of the most intense on record.

Auroras were reported all over the world and there were mass telegraph outages. Currents induced in the telegraph lines were strong enough to melt contacts, shock operators, and set some kinds of paper on fire.

Solar storms of this magnitude are now referred to as “Carrington-class.” One such storm occurred in 2012. The coronal mass ejection it produced *just* missed the Earth.

Image: NASA/STEREO

Significant update to my reference page on "Conventions, Definitions, Identities, and Formulas.”

Changes to:
* Hypersurfaces with a spacelike or timelike unit normal
* Small variations of the metric

This is a collection of useful results for folks working in gravitational physics and high-energy theory. It's a repository for things I frequently need, and includes some explicit results which (as far as I am aware) do not appear anywhere in the literature.

http://jacobi.luc.edu/Useful.html

@xek Hello!