The sky on
your birthday.
The Same Color Illusion
This image illustrates the 'same color illusion,' where squares A and B appear different but are actually the same color. It highlights how human perception can be ambiguous, even for seemingly direct observations like color. Similar illusions exist in astronomy, such as the apparent size of the Moon near the horizon. Automated measuring devices help overcome such perceptual biases.
Heavy matte paper, about 200 gsm, printed in the United States and shipped free. The card stays free, the print is the thing you keep.
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Released on your day
Space pictures released on your month and day in other years, or a few days either side. Each one is sharp enough to print as a poster.
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The Earth on your day The Earth on 4 October 2009 · Red Sea See it as a poster -
Released on 4 October 2024 Westerlund 1 (wide-field view) See it as a poster -
Released on 4 October 2010 Star formation fireworks in Orion See it as a poster -
Released on 4 October 2021 NGC 4676: When Mice Collide See it as a poster -
Released on 4 October 2005 NASA Space Observatories Glimpse Faint Afterglow of Nearby Stellar Explosion See it as a poster -
Released on 4 October 2021 A Dangerous Dance See it as a poster
In tropical astrology, 4 OCT 2009 falls under Libra (♎). The sign's window runs from 09-23 through 10-22. Libra is the only zodiac constellation named for an inanimate object, the scales of judgment. The Sun was crossing this region of the sky on 4 OCT 2009.
Questions about October 4, 2009
What space photo was released on October 4, 2009?
NASA's Astronomy Picture of the Day for October 4, 2009 was "The Same Color Illusion". It's the card at the top of this page.
What was the Moon's phase on October 4, 2009?
A full moon, about 100% lit.
What day of the week was October 4, 2009?
October 4, 2009 was a Sunday, day 277 of the 365 days in 2009.
What did the Sun and the Earth look like on October 4, 2009?
NASA's Terra satellite photographed the whole Earth that day. It's on this page, next to the card.
Is it free?
Yes. Seeing, sharing and downloading the card is free, and there's no account to make.