25 Enlightening Facts About Light And Vision

Light is probably more interesting than you think. For thousands of years light was just one of those things that people knew was there, they knew it was important, but never really thought too much about it. Without light you can’t see, that’s all they knew. It wasn’t until later that people realized light is unique. In the last several hundred years scientists have discovered just how unique light really is. For one, it is unlike any other substance in the universe. That’s right, it can be defined as a substance. How can that be? It’s because light can be both a wave and a particle…at the same time! Moreover, scientists found that light always travels the same speed, even if you shine it off of a moving object. This may not be immediately obvious, but if you shoot or launch anything else off a moving object then it’s velocity will be affected by the velocity of the object you are launching it from. For example, try throwing a tennis ball out of a car window. Not only will it be moving perpendicular to your car but it will also continue moving in the direction of your vehicle as well. Light doesn’t do that. These are 25 enlightening facts about light and vision.

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25

Thanks to time dilation, a person could actually travel thousands of light years in a normal human lifespan (traveling 28 years with 1 g of constant acceleration for the first 14 years would get you to the Andromeda Galaxy 2 million light years away)

Thanks to time dilation, a person could actually travel thousands of light years in a normal human lifespan (traveling 28 years with 1 g of constant acceleration for the first 14 years would get you to the Andromeda Galaxy 2 million light years away)Source: wikipedia, Image: pixabay
24

Time dilation is what happens when you approach the speed of light. After 1 year of traveling at near light speed if you came back to Earth you would come to find that potentially hundreds of years have elapsed here!

Time dilation is what happens when you approach the speed of light. After 1 year of traveling at near light speed if you came back to Earth you would come to find that potentially hundreds of years have elapsed here)Source: wikipedia, Image: pixabay
23

The human body is actually bioluminescent, which means that you produce light! Unfortunately that light is far too dim for you to see.

The human body is actually bioluminescent, which means that you produce light! Unfortunately that light is far too dim for you to seeSource: io9.com, Image: pixabay
22

In space, astronauts sometimes see bright flashes due to cosmic rays striking their retina. This doesn't happen down here on Earth thanks to protection from the magnteosphere.

In space, astronauts sometimes see bright flashes due to cosmic rays striking their retina. This doesn't happen down here on Earth thanks to protection from the magnteosphereSource: wikipedia, Image: pixabay
21

LED traffic lights have actually led to crashes. This is because they don't emit enough heat to melt potential snow cover during winter months.

LED traffic lights have actually led to crashes. This is because they don't emit enough heat to melt potential snow cover during winter monthsSource: abcnews.go.com, Image: pixabay
20

Tachyons are hypothetical particles that travel faster than the speed of light. They have imaginary mass (square root of -1) and experience time in reverse.

Tachyons are hypothetical particles that travel faster than the speed of light. They have imaginary mass (square root of -1) and experience time in reverse.Source: wikipedia, Image: pixabay
19

Some NASA images taken of the Earth at night once showed extremely bright lights in the middle of the desert in Australia. It turns out that a significant swath of the continent was engulfed in brush fires that burned even brighter than the coastal cities.

Some NASA images taken of the Earth at night once showed extremely bright lights in the middle of the desert in Australia. It turns out that a significant swath of the continent was engulfed in brush fires that burned even brighter than the coastal citiesSource: nasa.gov, Image: pixabay
18

Peacock feathers are actually brown. It is their microscopic structure (structural pigmentation) that causes them to reflect so many colors like red, blue, and green.

Peacock feathers are actually brown. It is their microscopic structure (structural pigmentation) that causes them to reflect so many colors like red, blue, and greenSource: wikipedia, Image: pixabay
17

Although the speed of light in a vacuum is constant (c), in different materials light may not travel or propagate as quickly.

Although the speed of light in a vacuum is constant (c), in different materials light may not travel or propagate as quickly.Source: wikipedia, Image: pixabay
16

Cherenkov radiation is what happens when a particle travels through a medium (like water) faster than light would. This radiation gives off a blue glow that is characteristic of underwater nuclear reactors.

Cherenkov radiation is what happens when a particle travels through a medium (like water) faster than light would. This radiation gives off a blue glow that is characteristic of underwater nuclear reactorsSource: wikipedia, Image: wikipedia
15

Although researchers are not entirely sure why, when some areas in Scotland and Japan changed their street lights from yellow to blue they saw a decrease in crime and suicide.

Although researchers are not entirely sure why, when some areas in Scotland and Japan changed their street lights from yellow to blue they saw a decrease in crime and suicideSource: psychcentral.com, Image: pixabay
14

A jiffy is actually an unit of time (how long it takes light to travel 1cm in vacuum)

A jiffy is actually an unit of time (how long it takes light to travel 1cm in vacuum)Source: wikipedia, Image: pixabay
13

Because of a genetic quirk called the photic sneeze reflex, about one third of the population will sneeze when looking at the sun.

Because of a genetic quirk called the photic sneeze reflex, about one third of the population will sneeze when looking at the sunSource: scientificamerican.com, Image: pixabay
12

Betelgeus is a star roughly 450 light years away that will explode within the next 300,000 years. When it does, it will light up the sky even brighter than the moon. In fact, it will be visible in the middle of the day

Betelgeus is a star roughly 450 light years away that will explode within the next 300,000 years. When it does, it will light up the sky even brighter than the moon. In fact, it will be visible in the middle of the daySource: earthsky.org, Image: pixabay
11

Some researchers are trying to create bioluminescent trees with the same enzymes found in jellyfish. This would provide a clean source of light for city streets at night

Some researchers are trying to create bioluminescent trees with the same enzymes found in jellyfish. This would provide a clean source of light for city streets at nightSource: huffingtonpost.com, Image: wikipedia
10

In 2001, Lene Hau, a physicist at Harvard, managed to stop a beam of light in its tracks

In 2001, Lene Hau, a physicist at Harvard, managed to stop a beam of light in its tracksSource: wikipedia, Image: wikipedia
9

The same particles that are responsible for creating the northern lights also cause clapping sounds to be heard. These sounds have led to numerous folk tales and legends.

The same particles that are responsible for creating the northern lights also cause clapping sounds to be heard. These sounds have led to numerous folk tales and legendsSource: space.com, Image: pixabay
8

Selenium is an insulator, meaning it doesn't conduct electricity. The catch is that this only holds true in the dark. As soon as you shine some light on the selenium it turns into a conductor.

Selenium is an insulator, meaning it doesn't conduct electricity. The catch is that this only holds true in the dark. As soon as you shine some light on the selenium it turns into a conductor.Source: wikipedia, Image: wikipedia
7

Humans actually have the ability to see ultraviolet light, it is just filtered out by the lens. Sometimes patients will be able to see into the UV spectrum following eye surgeries.

Humans actually have the ability to see ultraviolet light, it is just filtered out by the lens. Sometimes patients will be able to see into the UV spectrum following eye surgeriesSource: wikipedia, Image: pixabay
6

Although black holes themselves are invisible, the material falling into them is often quite bright. S5 0014+81 is a black hole that is so big it would be just as bright as our Sun from 6 billion times the distance! Thankfully it is farther than that!

Although black holes themselves are invisible, the material falling into them is often quite bright. S5 0014+81 is a black hole that is so big it would be just as bright as our Sun from 6 billion times the distance! Thankfully it is farther than that!Source: wikipedia, Image: pixabay
5

Stoplight Loosejaw is a deep sea fish that uses a red bioluminescent light to hunt for fish. This is quite sneaky because fish cannot sea red light!

Stoplight Loosejaw is a deep sea fish that uses a red bioluminescent light to hunt for fish. This is quite sneaky because fish cannot sea red light!Source: wikipedia, Image: wikipedia
4

The former dividing line between east and west Berlin can still be seen from space. West Berlin uses white colored lights while east Berlin still uses yellow colored lights.

The former dividing line between east and west Berlin can still be seen from space. West Berlin uses modern white colored lights while east Berlin still uses older yellow colored lights.Source: camyx.com, Image: wikipedia
3

If you put a plant that is normally green under green light it will most likely die. This is because green plants reflect green light (giving them the color) and absorb the others for photosynthesis

If you put a plant that is normally green under green light it will most likely die. This is because they reflect green light (giving them the color) and absorb the others for photosynthesisSource: wikipedia, Image: pixabay
2

The Centennial Lightbulb in California is the longest burning lightbulb. It has been on since 1901! (with a few interruptions during power failures)

The Centennial Lightbulb in California is the longest burning lightbulb. It has been on since 1901! (With a few interruptions during power failures)Source: wikipedia, Image: wikipedia
1

The sun is actually white when you look at it in space (not recommended). It is the atmosphere that scatters its light waves and makes it look yellow

The sun is actually white when you look at it in space (not recommended). It is actually the atmosphere that scatters its light waves and makes it look yellowSource: wikipedia, Image: pixabay


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