Science and Exploration

[Toughy]

I posted this in the Zombie thread....however it does belong here:

from HuffPo

Bats' Oral Sex Helps Prolong Copulation, Scientists Say (VIDEO)

http://www.huffingtonpost.com/2013/0...een&ref=topbar

[Corkey]

http://news.yahoo.com/scientists-pos...205206362.html


Looking for dark matter.

[dreadgeek]

Originally Posted by Corkey

http://news.yahoo.com/scientists-pos...205206362.html


Looking for dark matter.

You beat me to the punch on this the other day, Corkey. I started working on an explanation and it became a bit more complex. So, I wanted to ask would people find it helpful if I put together a short primer on dark matter, what it is and why it matters?

Cheers
Aj

[Corkey]

Originally Posted by dreadgeek

You beat me to the punch on this the other day, Corkey. I started working on an explanation and it became a bit more complex. So, I wanted to ask would people find it helpful if I put together a short primer on dark matter, what it is and why it matters?

Cheers
Aj

Great idea Aj, go for it!

[dreadgeek]

So, I said I'd do this a few days ago. I apologize for the delay:

Science advances not when someone exclaims "Eureka!" but when someone cocks their head and says, "well now, that's unexpected". There are a number of issues that caused astronomers, astrophysicists and cosmologists to say "well, I wasn't expecting that". I'll only take two because they are the easiest to explain and require no math to get to an understanding.

The first is the concept of gravity lensing. Gravity lensing is caused when the light of a very distant object is warped around an intervening mass like, say, a galaxy. As everyone knows, light moves from point A to point B and, as everyone is aware of from the idea of black holes, light can be affected by gravity. When this happens at astronomical distances what happens is that the object either appears as either a ring (known as an Einstein ring) or it'll appear slightly offset from where the object actually is. Now, if we know the approximate mass of a galaxy (which can be estimated from its size and density of stars) then we can know about how much refraction there should be. The problem then is that astronomers see more lensing than can strictly speaking inferred from the masses in between them and some distant light source. This begs the question of *why* this is happening.

The second concept is the spin of a galaxy. This is a bit more complicated. Think of a spiral galaxy like a solar system writ large. In the center of the galaxy is a hugely massive orbit (a supermassive black hole) and most of the mass of the galaxy is in that bulge in the center. Then there's the spiral arms. Calculating the rotational speed of a galaxy of a given size *should* be a pretty straightforward application of Newton's and Kepler's laws that work very well when applied to solar systems. The basic idea here is that the closer to the gravitational center an object is, the faster it rotates and the farther out it is, the slower it rotates. Except that's *not* what we see. Instead we see a near uniform rotational speed even at the outer extremities of the galaxy--for instance where our solar system is in relation to the rest of the Milky Way. Again, this begs the question of *why*.

Now, the proposed answer is that there is some 'missing' matter that we can't directly observe. This missing matter is called 'dark matter'. Why dark? Because it does not interact strongly with the electromagnetic force (light in all its form and splendor). Ordinary matter (the kind of stuff we and everything we can see) will interact with the electromagnetic force. For instance, someone walking into the room where you currently sit reading this can see you because all of the matter that makes you you is reflecting electromagnetism in the visible portion of the spectrum. Dark matter doesn't do that. Instead if it interacts with light at all it does so very weakly and all evidence, so far, is that it does not interact with it at all.

If this were all that there was to dark matter it would be almost impossible to find but fortunately this isn't the case. Dark matter *does* interact with itself and when it does it splits off into exotic particles that were predicted by physicists who started working on the problem. The experiment aboard the ISS (International Space Station) detected the kinds of particles that the theory predicted which is usually a sign that we're on the right track.

Dark matter and dark energy are *not* the same thing and shouldn't be confused with one another.

Cheers
Aj

[Corkey]

You're forgiven.
Understood that well, thank you.

[dreadgeek]

So since I mentioned dark energy I thought I would go ahead and talk about this subject as well. There's another problem in cosmology and it is this: the expansion of the Universe isn't slowing down. To understand why this is a problem it's necessary to go back to the very beginning: the Big Bang. So according to the prevailing model, at one point the whole of the Universe was contained in a space about the size of what is called the Planck length (10^-43 or 1 with 43 zeroes in front of it) which is the smallest anything existing can be said to be. For reasons that may forever be beyond our understanding this fantastically small object suddenly became *much* larger. This is the Big Bang. In the first few moments of the Universe spacetime grew hugely. Things settled down after a while, the balance of matter-antimatter tipped in favor of matter and it started to get cold enough for atoms to start to form. After the rapid inflation expansion started to slow down a bit and matter started clumping together to form stars and galaxies and all the rest of the things observable in the Universe.

Now, here's where things get interesting. Gravity is *always* attractive and is caused by the warping of spacetime by the presence of mass. The consequence of this is that what we should see is that over time, the expansion of the Universe should slow down and then, possibly, reverse coming together in a Big Crunch (or as Douglas Adams put it in Restaurant at the End of the Universe, a gnab gib). The problem is that we aren't observing this. In fact, not only has the expansion continued but it is still accelerating. This cries out for explanation.

That explanation is dark energy. *Some* form of energy, that we lack the means to detect at present levels of technology, is pushing the Universe apart. We don't know precisely what it is but there is a damn lot of the stuff whatever it is. This more or less seals the fate of the universe. Eventually what will happen is that all of the galaxies will be so far apart from one another that they will be too faint to see.

How do we know that the galaxies are all rushing away from one another? (on the whole, the Milky Way is going to eventually collide with the Andromeda galaxy because the greater mass of our galaxy is pulling the Andromeda galaxy toward us) We know because of what is called red shift. This is simply the familiar Doppler effect applied to light. When a siren is approaching you the pitch increases and as it speeds away from you the pitch decreases. The same thing happens to light (although we can't detect it because the distances light travels here on Earth can never be far enough to see any kind of shifting) but at the astronomical level stars or galaxies moving away from us have their light shifted toward the red part of the spectrum. The more red shift the farther away you are from the observed object.

Cheers
Aj

[Jean_TX]

Scientists are further investigating a phenomenon called 'dark lightning' : "Dark lightning that is almost invisible within clouds may regularly blast airline passengers with large numbers of gamma rays, scientists find." Although it sounds ominous, the effects on the body may not be dangerous. The full article can be read at http://www.livescience.com/28594-dar...assengers.html

[dreadgeek]

I know, it doesn't look scary. It's actually kind of beautiful which is why I'm using it as my current desktop background. But what *is* it? It's a map of orbits of every *known* Potentially Hazardous Asteroid (PHA). In other words, the map of every rock larger than 460 feet that has an orbit that passes uncomfortably close to the Earth. Close, because we're talking about space here, means within 5 million miles. To give you a sense of scale, the Moon is ~250,000 miles from the Earth. Five million seems like a lot of distance but when you consider that when it is at its closest, Venus is 38 million miles away. So we're talking very big numbers. The problem is that Earth has a serious gravitational pull and something within 5 million miles of the Earth is certainly going to be influenced by its gravity. How many objects are we talking about? Around 1,400! That's when it gets scary.

The reason why the size matters is that mass matters. Earth actually gets hit on occasion by fairly small pieces of rock but it's the large pieces that wreak havoc on the planet. That said, nothing in that graphic is in any real serious danger of hitting the planet in the next century. But longer out...? Something around 1,000 feet strikes the Earth approximately every 80,000 years. To give you sense of scale here, the asteroid that most likely blasted a chunk out of the Yucatan peninsula and likely delivered the coup de grace to the dinosaurs was somewhere in the range of 6 miles in diameter. Think Manhattan hitting the Earth.

Image page

Cheers
Aj

[Electrocell]

Brain-eating amoebas: What you need to know


Naegleria fowleri: A look at the brain-eating amoeba and how to avoid it.

Rex Features

A look at brain tissue infected with Naegleria fowleri.
MSN News 3 hr ago | By Heather Smith, MSN News of MSN News





Florida health officials have issued a warning for swimmers after a boy contracted Naegleria fowleri. Here's what you need to know about the deadly amoeba.






The Florida Department of Health has issued a warning for swimmers after a 12-year-old boy in the southwestern part of the state contracted a rare brain infection caused by Naegleria Fowleri (N. fowleri) while knee boarding with some friends in a water-filled ditch. Officials said that high water temperatures and low water levels combine to create the perfect breeding ground for N. fowleri, and warned the public "to be wary when swimming, jumping or diving in freshwater."

This latest case of infection comes less than a month after an Arkansas girl ended up in a hospital, fighting for her life. Here, we look at what it is and how to avoid the sometimes deadly brain-eating amoeba.

What is it?

N. fowleri is an amoeba that lives in warm freshwater, such as ponds, lakes and hot springs. It also thrives in the soil around it. Normally, it eats the bacteria found in these places, but when presented with the opportunity, it will eat brains. There is no evidence of this organism living in salt water. It is an amoeba belonging to the groups Percolozoa or Heterolobosea.

The amoeba invades the body and causes a rare brain infection known as primary amebic meningoencephalitis, or PAM, that eats away at brain tissue and is usually fatal, according to the Centers for Disease Control.

How do you get it?

N. fowleri invades the central nervous system through the nose. From there, the amoeba moves the along olfactory nerve fibers into the brain, where it uses its suckers to devour brain cells. It's difficult to treat because by the time it's been diagnosed, it's already caused significant damage.

N. fowleri is most often caught by people who have been swimming underwater, but it's also thought to be transmitted through inhaling infected dust. Last year, two people died in Louisiana after they used tap water to flush out their sinuses.

Where does it thrive?

Freshwater — especially warm freshwater. Most cases have occurred in Southern or Southwestern states, especially Texas and Florida. It's been known to show up in swimming pools and hot tubs that haven't been properly chlorinated. Last month, a popular water park in Arkansas voluntarily closed after a 12-year old girl who swam there was diagnosed with N. fowleri

How can you avoid them?

N. fowleri infections are very rare — they've only killed 128 Americans between 1962 and 2012, according to the Centers for Disease Control. But you can reduce your risk of catching it by keeping your head out of the water when you're swimming in water that hasn't been chlorinated. If you're flushing your sinuses, be sure to use distilled or recently boiled water.

How is it treated?

N. fowleri is treated with antifungals, antibiotics and steroids. The most recent survivor, a 12-year-old girl infected at an Arkansas water park, was also treated with an experimental breast cancer drug.

——

Join MSN News on social

Share your point of view with us on Facebook

Get the latest news and updates on Twitter

See photos and videos on Tumblr

[dreadgeek]

As Phil Plaitt points out in this article, every year around this time people start spreading this Internet meme that Mars will look as large as the Moon in the night sky. It's a hoax. It will always be a hoax because Mars *never* gets close enough to Earth to look as large as the Moon. At its closest pass Mars gets within 35 million miles of Earth. At its farthest point (where it is now) it is about 210 million miles from Earth (it's currently on the far side of the Sun from us). Mars is a relatively small planet. It is half the size of Earth. The moon is about half the size of Mars. The moon is just next door (250,000 miles) compared with with the 35 million miles between Earth and Mars at their closest. So in order for this meme to be true, an object only twice the size of our moon would have to appear to be the same size even though Mars is two and a half orders of magnitude farther away from Earth! That's not optically *possible*. With the naked eye Mars can only ever look like a tiny dot in the sky. If it ever *were* in an orbit that would make it look the same size as the Moon that would be a very interesting day on Earth (interesting, here, in the "Oh God, Oh God, we're all gonna die" sense).

So if you see a meme on Facebook telling you that if you go outside sometime in the next week it'll appear as if the planet has two moons, know that someone is pulling your leg because they are.

Cheers
Aj

[dreadgeek]

It was pointed out to me that 2.5 orders of magnitude might be a little difficult for people to grasp intuitively so to give you a sense of scale I'll use this. I live in Portland, OR but I work in Hillsboro, OR. That's about 20 miles one-way, door-to-door from home to office. One order of magnitude would be ten times that far or 200 miles. That would put me in Grants Pass, OR or just north of Seattle, WA. Two orders of magnitude would be 2000 miles away so that would be in the Detroit, MI region. Two and half orders of magnitude would be 3000 miles or somewhere in northern Maine.

So to understand the scale of distance between the Moon and Earth compared to Mars and Earth, do this; take a city that is around 25 miles from you. Find a city that is ten times that distance (one order of magnitude) away. Now, find a city that is 100 times further away (two orders of magnitude). Now find another city that is half-again as far away (two and half orders of magnitude) and THAT is the ratio of distance scaled down to terrestrial scales. . So, to scale, the Earth is as far away from Mars as Portland, OR is from northern Maine. The Earth is as far away from the Moon as Portland, OR is from Seattle WA.

Originally Posted by dreadgeek

As Phil Plaitt points out in this article, every year around this time people start spreading this Internet meme that Mars will look as large as the Moon in the night sky. It's a hoax. It will always be a hoax because Mars *never* gets close enough to Earth to look as large as the Moon. At its closest pass Mars gets within 35 million miles of Earth. At its farthest point (where it is now) it is about 210 million miles from Earth (it's currently on the far side of the Sun from us). Mars is a relatively small planet. It is half the size of Earth. The moon is about half the size of Mars. The moon is just next door (250,000 miles) compared with with the 35 million miles between Earth and Mars at their closest. So in order for this meme to be true, an object only twice the size of our moon would have to appear to be the same size even though Mars is two and a half orders of magnitude farther away from Earth! That's not optically *possible*. With the naked eye Mars can only ever look like a tiny dot in the sky. If it ever *were* in an orbit that would make it look the same size as the Moon that would be a very interesting day on Earth (interesting, here, in the "Oh God, Oh God, we're all gonna die" sense).

So if you see a meme on Facebook telling you that if you go outside sometime in the next week it'll appear as if the planet has two moons, know that someone is pulling your leg because they are.

Cheers
Aj