The Holographic Principle
13.09.2009

Is this picture worth a thousand words? According to the Holographic Principle, the most information you can get from this image is about 3 x 10 65 bits for a normal sized computer monitor.

The Holographic Principle and a Teapot
3.10.2021

Sure, you can see the 2D rectangle of colors, but can you see deeper? Counting color patches in the featured image, you might estimate that the most information that this 2D digital image can hold is about 60 (horizontal) x 50(vertical) x 256 (possible colors) = 768,000 bits.

A Solar Eclipse from the Moon
7.04.2014

Has a solar eclipse ever been seen from the Moon? Yes, first in 1967 -- but it may happen again next week. The robotic Surveyor 3 mission took thousands of wide angle television images of the Earth in 1967, a few of which captured the Earth moving in front of the Sun.

Cheering a Total Solar Eclipse
15.03.2016

What would you do if you saw the Sun disappear? Quite possibly: cheer. That's what many exuberant sky watchers did across Indonesia during a total eclipse of the Sun last week. There and then, the land and sky went dark during the day as our Sun disappeared for a few minutes behind our Moon.

How Much is That Comet in the Window?
27.03.1996

The above true-color photo taken March 25th shows Comet Hyakutake passing below the stars of the Big Dipper. Many astronomy enthusiasts delight in helping people in their local community see the comet. Both Jerry Bonnell and I (RJN) from APOD have been so inclined - both now and when Comet Halley came by in 1986.

APOD Turns Eighteen
16.06.2013

The first APOD appeared eighteen years ago today, on 1995 June 16. Although garnering only 14 pageviews on that day, we are proud to estimate that APOD has now served over one billion space-related images over the past eighteen years.

Here Comes Comet Hyakutake
13.03.1996

The reaction of ancient peoples to the appearance of bright comets has toppled empires, de-throned kings, and been taken as a sign of great things to come. Probably some of these comets did not get as bright as Comet Hyakutake ("hyah-koo-tah-kay") will in the next two weeks.