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That’s new: circumcision seems to protect against HIV

Hank Green tells us about experiments that were done in which circumcised people were shown as being protected by the fact that the foreskin was cut off. It seems that there are some weak cells in there that are prone to HIV infection. Removing those protects one against HIV more that you’d think.

In any case, circumcision should be an adult’s choice, not performed on kids.

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Urine is NOT sterile

So, don’t feed into the crap of those who say otherwise. Urine is full of bacteria and, if you need a hot water, simply use hot water and not your urine. Urine which has less than 100 000 colonies in 1 ml of urine will be counter as sterile, but there are many bacteria which are not yet measured in the labs and you do have those in the urine.

so, urine is NOT sterile. It has bacteria all over the place.

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Scishow outtakes remix. Have fun!

SciShow explains a lot of science things, but they also have a lot of fun. In the mix from above you will see the fun at work. Have fun with science!

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SciShow: what happens in Chernobyl’s exclusion zone?

Hank Green tells us that life in Chernobyl has continued and, without the humans around to spoil the party, tons of wild animals have come in there and made it their home. Many plants and animals seen to thrive in there, although it seems that the radioactivity really hurts most of the animals.

Trees. The dead trees remained the same ad when the reactor exploded back almost 30 years ago. Chernobyl is still an exclusion zone, a place where you shouldn’t go.

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SciShow: why do joints pop and crack?

The bones do not come in direct contact with each other in your body, but instead and articular cartilage provides the link. These articular cartilage are kept lubricated by synovial fluid which is generated by the synovial membrane.this membrane covers the articulate cartilage.

When you pop and crack your joints then you pull your bones away form each other. That forces the synovial membrane to expand and thus the synovial fluid from inside experiences decreased pressure and gases dissolved in it, carbon dioxyde and oxygen, will be released as gases inside the fluid.

The pop you hear is the bubble forming inside the synovial membrane. We do not have conclusive data to know if the bones popping and cracking is dangerous.

See the entire system that keeps your bones together: the articulate cartilage is surrounded by the synovial membrane which generated synovial fluid that fills in the gaps in there. This way the bones to not touch directly. the ligamets are used to squeeze or stretch the muscles and simply go over the synovial membrane.

See image:

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Coal fires that burn for 50 years? Yes, in Pennsylvania and in dozens of other places

Earth is truly amazing, but it is also a place of utter fear. How can it be that coal fires burn for over 50 years and some of them will burn for hundreds of years to come? Hank Green, from SciShow, explains how those coal fires show up and what we can do about it.

Spoiler alert: there’s nothing we can do about it. We just need to go away from those places.

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I didn’t knew that: bright light can make you sneeze

SciShow comes again with some interesting facts about the world we live in. In some cases, if we get into the bright light from a darker pace we might start sneezing and this can happen because of the way the trigeminal nerve, the one that handles our face, interacts with the optical nerve, since they are close together.

In any case, when you get to bright light and sneeze you may be one of the few privileged to feel light in this way. Mwahaha 😀

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Blood types. What A, B, O, AB and Rh mean?

SciShow explains what blood types are and which is compatible to which in case a transfusion is needed. There are four blood groups A, B, AB, and O and each of these groups can have a negative or positive Rh, making humans beings that have in a total of 8 blood types A Rh+, A Rh-, B Rh+, B Rh- and so on.

We have different blood types, because we have different immune systems. Our immune system protects the cells of our bodies because it recognizes the antigens, the proteins the cells are covered with like a nametag, and attacks cells that does not have our antigens. If the immune systems sees antigens that do not belong to us, then it triggers the release of antibodies to catch and destroy those foreign cells.

The red blood cells have two main types of antigens: agglutinogens A and B. They activate antibodies that attack invaders. If you have aggulinogen A, then you do not have antibodies for A, but you have antibodies for B and so on. This is why A cannot accept blood from anyone except A type as the immune system would attack blood type B, for example, and destroy it.

Here is a table from the video to better understand the issue:

We also have another set of antigens in the blood cells: Rh antigens, or Rhesus. If you have them, you are Rh positive, if not, then you’re Rh negative. This is how you get 8 blood types: A, B, AB, O AND Rh -/+.

So, given the antibodies we have in our bodies based on the antigens on our blood cells, tranfusion needs to make sure we are compatible. So, AB, which has no antibodies for other blood types can accept A, B, AB and O, but O can accept only from O as it has antibodies A and B.

Image, credit Scishow:

Also, given Rh antigens, Rh positive can accept Rh+ adn Rh-, but Rh- can accept only from Rh-.
Image credit SciShow:


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Humans in the new stage: exoplanets hunters

I cannot thank US enough for their space programme. Romania, where I live now, is acting like a credulous servant for the US mainly, but I admire US not for its financial status, or military and so on, but for the fact that US has a ton of programmes for space search, from telescopes, to satellites and to space drones.

Thanks to US, we, humans, have long entered the era of exoplanet hunters and space dust gatherers. Hank Green, from SciShow, explains what exoplanets are, where they come from and that we are a gazillion of such planets out there.

Is there life in those tens of thousands of Earth-like planets in the Milky Way? Most certainly yes. Intelligent life? Maybe yes, maybe no. Until we will be able to bend space-time the way we want to travel to those distant planets we can only dream of the day when we’ll meet another intelligent being besides us int he Universe.

That day will be a turning point in our history. We were meant to show up on Earth, but we were meant to travel to the stars.

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Russia’s Kola Superdeep Borehole – the deepest hole in the World

Russia’s Kola Superdeep Borehole goes for more than 12 kilometers into Earth’s crust and is, to date, the deepest ever hole drilled by humans. At such depths the temperature is about 180 degrees Centrigrade or over 300 degrees Fahrenheit and the rock behaves like plastic.

Hank Green tells us that the hole took 25 years to be built and was shut close in 1995. The scientists had to invent new devices to make such deep holes. They wanted to find out if they can reach the mantle and to see how it behaves. They could not reach the mantle because Earth’s crust is over 30 kilometers thicks so, we’ll get to the center of the Earth in the future, but not now 😀