We all know the harmful effects of the sun touching our skin, so we ready ourselves with sunscreen to block the rays. But what about our eyes? What would happen if we happened to stare directly at the sun?
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Whether it’s to map the stars, spy on other planets, or study the sun, humans have been looking to the skies for millennia. But some objects are safer to observe than others.
For example, astronomer Mark Thompson put a pig’s eye behind a regular telescope aimed at the sun and it burned a hole straight through the lens in about 20 seconds.
Now, looking at the sun through a telescope is an especially terrible idea but just how bad is it to glance up with the naked eye?
On a clear day, the sun shines up to 5,000 times brighter than an average light bulb. When something that bright strikes your eye, a few things can happen.
If it’s only for a moment, the worst you’ll experience is a blurry splotch on your vision called an after image.
Normally, light reaches the retina at the back of your eye, where it triggers photoreceptors that relay the information to your brain. This is how you are able to see anything.
But bombard them with too much light at once, and you can actually damage the cells and proteins that help them process light. Since your retina has no pain receptors, the damage won’t hurt, but it will leave that blurry splotch on your vision.
Usually, it clears up in a few minutes that is, unless you keep staring.
Now, you’re doing more than just overloading your retina. For starters, you’re giving your eyes an abnormally high dose of UV radiation the same stuff that causes sunburns. Like your skin, the cornea at the front of your eye can also burn. And that will hurt.
The cornea protects the rest of your eye and is therefore covered in pain receptors that alert you whenever a pesky eyelash is on the loose.
But UV radiation isn’t the only issue. Too much visible light can penetrate your eye and damage the retinal tissue, which causes a condition called solar retinitis. This means parts of your retina can no longer process light normally, so you can end up with entire chunks of your vision blurred out.
Depending on the extent of the damage, recovery can take weeks, months, and in severe cases over a year. But in rare cases, the damage is so extreme it never heals, leading to a rare condition called solar retinopathy. This usually only shows up in reckless eclipse gazers.
Turns out, during a solar eclipse, most of the sun’s light is blocked, which actually can trick your brain into thinking it’s safe to stare.
Normally, our bodies have a built-in defense mechanism against staring at the sun. Specifically, when we squint we look up, which minimizes the amount of light coming in and protects our cornea and retina.
But during a solar eclipse, the sun doesn’t appear bright enough to trigger our defense mechanisms so we can end up staring for longer than is safe.
Suffice it to say, there’s nothing good about staring at the sun. So do your eyes a favor and avoid looking at it.
After all, there are around 6,000 stars in the night sky you can safely observe for as long as you wish.
This site provides links to random videos hosted at YouTube, with the emphasis on random.
The original idea for this site actually stemmed from another idea to provide a way of benchmarking the popularity of a video against the general population of YouTube videos. There are probably sites that do this by now, but there wasn’t when we started out. Anyway, in order to figure out how popular any one video is, you need a pretty large sample of videos to rank it against. The challenge is that the sample needs to be very random in order to properly rank a video and YouTube doesn’t appear to provide a way to obtain large numbers of random video IDs.
Even if you search on YouTube for a random string, the set of results that will be returned will still be based on popularity, so if you’re using this approach to build up your sample, you’re already in trouble. It turns out there is a multitude of ways in which the YouTube search function makes it very difficult to retrieve truly random results.
So how can we provide truly random links to YouTube videos? It turns out that the YouTube programming interface (API) provides additional functions that allow the discovery of videos which, with the right approach, are much more random. Using a number of tricks, combined some subtle manipulation of the space-time fabric, we have managed to create a process that yields something very close to 100% random links to YouTube videos.
YouTube is an American video-sharing website headquartered in San Bruno, California. YouTube allows users to upload, view, rate, share, add to playlists, report, comment on videos, and subscribe to other users. It offers a wide variety of user-generated and corporate media videos. Available content includes video clips, TV show clips, music videos, short and documentary films, audio recordings, movie trailers, live streams, and other content such as video blogging, short original videos, and educational videos. Most content on YouTube is uploaded by individuals, but media corporations including CBS, the BBC, Vevo, and Hulu offer some of their material via YouTube as part of the YouTube partnership program. Unregistered users can only watch videos on the site, while registered users are permitted to upload an unlimited number of videos and add comments to videos. Videos deemed potentially inappropriate are available only to registered users affirming themselves to be at least 18 years old.
YouTube and selected creators earn advertising revenue from Google AdSense, a program which targets ads according to site content and audience. The vast majority of its videos are free to view, but there are exceptions, including subscription-based premium channels, film rentals, as well as YouTube Music and YouTube Premium, subscription services respectively offering premium and ad-free music streaming, and ad-free access to all content, including exclusive content commissioned from notable personalities. As of February 2017, there were more than 400 hours of content uploaded to YouTube each minute, and one billion hours of content being watched on YouTube every day. As of August 2018, the website is ranked as the second-most popular site in the world, according to Alexa Internet, just behind Google. As of May 2019, more than 500 hours of video content are uploaded to YouTube every minute.
YouTube has faced criticism over aspects of its operations, including its handling of copyrighted content contained within uploaded videos, its recommendation algorithms perpetuating videos that promote conspiracy theories and falsehoods, hosting videos ostensibly targeting children but containing violent and/or sexually suggestive content involving popular characters, videos of minors attracting pedophilic activities in their comment sections, and fluctuating policies on the types of content that is eligible to be monetized with advertising.