Always Check Your Blind Spot
(Check the end of this post for a cool way to test your eyes’ blind spot!)
Humans have fairly good vision, as the animal world goes. Perhaps not as advanced as some ultraviolet-sensing birds or the super-seeing mantis shrimp, which can see circularly polarized light from UV to infrared, but pretty good. But along the evolutionary path that our eyes took to become what they are today, they left a blind spot … literally.
The rod and cone cells that make up the light-sensing part of the retina are wired from the inside, like a camera whose interior is filled with wires. All of those wires have to exit out the back of the eye, leaving a tiny hole in the retina where you can’t see anything:
Our eyes are on the left in the image above. The eyes on the right? Cephalopod eyes, like those of squid, have retinas that are wired from beneath and don’t have a blind spot. This is probably why we are doomed to be conquered by them …
Want to test your blind spot? Open up the “R/L” image at the top of this post, then close your right eye. Stare at the letter “L” with your left eye and move your head closer and farther from the screen to watch the other letter disappear.
Rinse, repeat, freak out.
The continental U.S. overlaid on the Moon, for your daily dose of perspective. Whoa. Compare the size of the craters to our biggest cities!
To take your dose of perspective to the next level, check out this video from Veritasium on just how far away the Moon is from the Earth (Hint: Much farther than most people think):
Searching for Mathematical Love
Go ahead. Search for this on Google :)
5 + (-sqrt(1-x^2-(y-abs(x))^2))*cos(30*((1-x^2-(y-abs(x))^2))), x is from -1 to 1, y is from -1 to 1.5, z is from 1 to 6
In #Astrophotography, star trails are a type of photograph that utilizes long-exposure times to capture the apparent motion of stars in the night sky due to the rotation of the Earth.
A star trail photograph shows individual stars as streaks across the image, with longer exposures resulting in longer streaks. Typical exposure times for a star trail range from 15 minutes to several hours, requiring a ‘bulb’ setting on the camera to open the shutter for a longer period than is normal. Star trails have been used by professional astronomers to measure the quality of observing locations for major telescopes.
How To: Star trail photographs are captured by placing a camera on a tripod, pointing the lens toward the sky, and allowing the shutter to stay open for a long period of time.
Star trails are considered relatively easy for amateur astrophotographers to create. Photographers generally make these images by using a SLR camera with its lens focus set to infinity. A cable release allows the photographer to hold the shutter open for the desired amount of time.
my favourite poem. always reblog
NASA IOTD | 2013 Feb 15
This is an image of magnetic loops on the sun, captured by NASA’s Solar Dynamics Observatory (SDO). It has been processed to highlight the edges of each loop to make the structure more clear.
A series of loops such as this is known as a flux rope, and these lie at the heart of eruptions on the sun known as coronal mass ejections (CMEs.) This is the first time scientists were able to discern the timing of a flux rope’s formation. (Blended 131 Angstrom and 171 Angstrom images of July 19, 2012 flare and CME.)
Robyn’s on tumblr!