Formulas Physics

Ganymede global geological map and global image mosaic.

USGS Astrogeology Science Center.

Clever way to remember the first few digits of Pi.

Every satellite around Earth

via reddit

NASA's $850-million mission to Mars is about to launch — here are 12 incredible facts you probably didn't know about the red planet

Martian volcano Olympus Mons is more than twice as high as Hawaii’s Mauna Loa, the tallest mountain on Earth from top to bottom.

Compared to the Grand Canyon on Earth, Valles Marineris on Mars is nearly five times deeper, about four times longer, and 20 times wider.

The red planet doesn’t have plate tectonics, which is what causes most quakes on Earth. But rising plumes of magma could trigger Mars quakes, as could meteorite impacts and the contraction of the world due to cooling. InSight will listen for them with its seismometer.

Martian oceans also had tsunamis like those on Earth. The tallest may have reached as high as 400 feet, just slightly shorter than the London Eye.

Like Earth, Mars has ice caps at its poles. The northern cap is up to 2 miles deep, is a mix of water and carbon dioxide, and covers an area slightly larger than Texas.

The average surface temperature on Mars is -81˚F, 138 degrees chillier than on Earth. But on a mid-summer day at the red planet’s equator, temperatures can peak at a balmy 95˚F.

Billions of years ago, Mars had oceans and flowing water. But adding them up would give you just 1.5% of all water on Earth today.

Mars has almost as much surface as Earth has land — but that doesn’t account for the 71% of Earth that’s covered in water.

The Martian atmosphere is 61 times thinner than Earth’s, and it consists almost entirely of carbon dioxide, which makes up just 0.04% of Earth’s atmosphere.

On Earth, sunsets are a brilliant mix of reds, pinks, oranges, yellows, and other colors. But on Mars they’re blue. Because air is dozens of times less dense on the surface of Mars than it is on our planet, white sunlight refracts less — leading to fewer colors (primarily blues).

Missions to Mars have become much rarer — after 23 launches in the 1960s and 1970s, we’ve launched just 10 in the new millennium (so far).

Getting to Mars is hard: About a third of the missions launched have failed.

Starburst Galaxy M94 from Hubble

Nikola Tesla once paid an overdue hotel bill with a ‘working model’ of his ‘death beam’. He warned the staff never to open it, describing it as a war-ending particle weapon that could stop invading armies and make warfare pointless. 

After his death in 1943, someone finally pried the box open and found nothing but a bunch of harmless old electrical components. 

(Source, Source 2)

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