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NASA
Course: NASA > Unit 2
Lesson 4: SpectroscopyUltraviolet waves (1801)
Created by NASA.
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What if there wasn't an ozone layer(7 votes)
If there was no ozone the UV-A, B, C would reach the earth's surface. This leads to skin cancer in humans. In genera it affects all the life on earth. Hence it is necessary to protectthe ozone layer.
For more information n ozone check out:
https://en.wikipedia.org/wiki/Ozone
and ozone layer depletion:
https://en.wikipedia.org/wiki/Ozone_depletion(3 votes)
Why is there more ozone depletion over Antarctica as compared to other parts of the Earth?1:55(4 votes)- when making a space suit which is most harmful ray that can burn humans?(1 vote)
UV rays are what cause sunburn. Although, when making a space suit, temperature is perhaps the biggest problem. A space suit has 28 layers to protect astronauts from the extreme temperatures of space.(4 votes)
If our atmosphere blocks the most harmful UV rays, would you be in more danger on a planet with less atmosphere (like Mars) from UV light from the Sun?(2 votes)- Yes, the ionizing(electromagnetic)radiation would be the cause to skin cancer and a lot of other diseases.(3 votes)
how can the paper turn black it just doesn't seem like it would be able to that because the rest of it is a rainbow.could someone please explain?!(1 vote)- It is photographic paper (not normal paper) is sensitive to UV rays. Because of high energy possessed by UV rays, it damages that paper and turns it into black .(3 votes)
How does sunscreen block the UV rays?(2 votes)
It has ingredients that either reflect or absorb UV wavelengths.(2 votes)
Are ultra violet waves dangerous?(1 vote)
As explained in the video, yes. They cause sunburns, and, in extreme cases, skin cancer.(1 vote)
- Are uvc waves obsorbed best because the earth is getting rid of them?(1 vote)
Do greenhouse gases actually reduce the ozone layer's thickness of our planet?(1 vote)- Greenhouse gasses do not, but CFCs generated by certain products do break ozone molecules. These products have been almost universally banned and the ozone layer is currently regenerating from the damage that has been done.(1 vote)
- Without the ozone layer, wouldn't we die?(1 vote)
1:55Video transcript
Swirling spiral arms of galaxy M33 can be seen in visible light, but the true extent of these spiral arms are revealed in ultraviolet light. Just as a dog can hear a whistle just outside the range of human hearing, bugs can see light just outside the range our eyes can see. A bug zapper emits this ultraviolet light to attract insects. Johann Ritter conducted an experiment in 1801 to find out what, if any, electromagnetic waves are beyond violet. Ritter knew that photographic paper would turn black more rapidly in blue light than in red light. So he tried exposing the paper beyond the violet end of the visible spectrum. Sure enough, the paper turned black proving the existence of light beyond violet, ultraviolet rays These ultraviolet rays, or UV radiation, vary in wavelength from 400 nanometers to 10 nanometers and can be subdivided into 3 regions: UV-A, UV-B and UV-C. Visible light from the Sun passes through the atmosphere and reaches the Earth's surface. UV-A, long wave ultraviolet, is the closest to visible light. Most UV-A also reaches the surface. But shorter wavelengths, called UV-B, are the harmful rays that cause sunburn. Fortunately, about 95% of these harmful UV-B rays are absorbed by ozone in the Earth's atmosphere. UV-C rays are the shortest and most harmful and are almost completely absorbed by our atmosphere. The Ozone Monitoring Instrument aboard NASA's Aura satellite detects ultraviolet radiation to help scientists study and monitor the chemistry of our atmosphere, including UV absorbing ozone. While atmospheric protection from harmful UV radiation is good for humans... it complicates the study of naturally produced UV rays in the Universe, by scientists here on the Earth's surface. Young hot stars shine most of their light beyond the visible light spectrum at ultraviolet wavelengths. Scientists need telescopes in orbit above the Earth's UV absorbing atmosphere to find and study these UV-bright regions of star formations in distant galaxies. New young stars in the spiral arms of galaxy M81 can be seen in this Galaxy Evolution Explorer, GALEX, image from NASA. Chemical substances, both atoms and molecules, interact with UV light making this region particularly interesting to scientists. An ultraviolet instrument aboard Cassini has detected hydrogen, oxygen, water ice, and methane in the Saturn system. UV data have also revealed details of Saturn's aurorae. Scientists also use UV waves shining from distant stars to view permanently shadowed regions of lunar craters. The Lyman-Alpha Mapping Project, or LAMP, instrument aboard NASA's Lunar Reconnaissance Orbiter can use this faint star-shine to look for possible water ice on the moon. Ultraviolet rays may be harmful to humans, but they are essential to studying the health of our planet's protective atmosphere and give us valuable clues to the formation and composition of distant celestial objects.