#Science

nudityandnerdery

Ion Propulsion…What Is It?

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Ion thrusters are being designed for a wide variety of missions – from keeping communications satellites in the proper position to propelling spacecraft throughout our solar system. But, what exactly is ion propulsion and how does an ion thruster work? Great question! Let’s take a look:

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Regular rocket engines: You take a gas and you heat it up, or put it under pressure, and you push it out of the rocket nozzle, and the action of the gas going out of the nozzle causes a reaction that pushes the spacecraft in the other direction.

Ion engines: Instead of heating the gas up or putting it under pressure, we give the gas xenon a little electric charge, then they’re called ions, and we use a big voltage to accelerate the xenon ions through this metal grid and we shoot them out of the engine at up to 90,000 miles per hour.

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Something interesting about ion engines is that it pushes on the spacecraft as hard as a single piece of paper pushes on your hand while holding it. In the zero gravity, frictionless, environment of space, gradually the effect of this thrust builds up. Our Dawn spacecraft uses ion engines, and is the first spacecraft to orbit two objects in the asteroid belt between Mars and Jupiter.

To give you a better idea, at full throttle, it would take our Dawn spacecraft four days to accelerate from zero to sixty miles per hour. That may sounds VERY slow, but instead of thrusting for four days, if we thrust for a week or a year as Dawn already has for almost five years, you can build up fantastically high velocity.

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Why use ion engines? This type of propulsion give us the maneuverability to go into orbit and after we’ve been there for awhile, we can leave orbit and go on to another destination and do the same thing.

As the commercial applications for electric propulsion grow because of its ability to extend the operational life of satellites and to reduce launch and operation costs, we are involved in work on two different ion thrusters of the future: the NASA Evolutionary Xenon Thruster (NEXT) and the Annular Engine. These new engines will help reduce mission cost and trip time, while also traveling at higher power levels.

Learn more about ion propulsion HERE.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com

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emily84
gaymilesedgeworth:
“ sorthvania:
“ naamahdarling:
“ sonneillonv:
“ ohfortheloveofcas:
“ mentalfacts:
“ Fact# 5857: Henrietta Lacks died in 1951. The tumor that killed her has been alive and growing to this day. The tumor is immortal and was used to...
mentalfacts

Fact# 5857: Henrietta Lacks died in 1951. The tumor that killed her has been alive and growing to this day. The tumor is immortal and was used to progress the Polio vaccine and is the jumping point for most human cell research to this day. Scientists have grown some 20 tons of her cells.

ohfortheloveofcas

They forgot the part where they took the cells and grew them without her consent.

sonneillonv

They also forgot the part where to this day her family and still-living descendants have not received any compensation for the use of her stolen cells.

naamahdarling

They also also forgot the part where she was Black.

sorthvania

This is a book you need to read.

gaymilesedgeworth

As long as this is on my dash, I’d like to mention the Henrietta Lacks Foundation?

Henrietta was a poor black tobacco farmer whose cancer cells, taken without her knowledge, became one of the most important tools in medicine, with damaging consequences for her family who today can’t afford access to the health care advances their mother’s cells helped make possible. The Foundation strives to provide financial assistance to needy individuals who have made important contributions to scientific research without personally benefiting from those contributions, particularly those used in research without their knowledge or consent. 

[…]

The Foundation’s goal is to continue to help the Lacks family as well as others with similar needs who may qualify, such as family members and descendants of research subjects used in the famous Tuskegee Syphilis Studies, those injected with sexually transmitted diseases without their knowledge by the US Government, and others. To qualify for a grant in any of the eligible categories, an applicant must prove financial need and have made, or be the family member or descendant of someone who has made, a significant contribution to scientific research as a research subject without personal benefit, including those who have unwillingly or unknowingly been used in research or contributed biological materials for research.

HistoryScienceerasureracismHenrietta Lacks
qdork-deactivated20200126
we-are-star-stuff:
“ What lies outside the universe? Physicists have long studied the nature of the universe. But some go a step further into the unknown (and probably unknowable), contemplating what lies outside the boundaries of our universe.
Is it...
we-are-star-stuff

What lies outside the universe?

Physicists have long studied the nature of the universe. But some go a step further into the unknown (and probably unknowable), contemplating what lies outside the boundaries of our universe.

Is it possible that something else exists beyond existence? Yes. Here are five theories about what that “something” might be.

The “outside the universe” question gets tricky right off the bat, because first you have to define the universe. One common answer is called the observable universe, and it’s defined by the speed of light. Since we can only see things when the light they emit or reflect reaches us, we can never see farther than the farthest distance light can travel in the time the universe has existed. That means the observable universe keeps getting bigger, but it is finite – the amount is sometimes referred to as the Hubble Volume, after the telescope that has given us our most distant views of the universe. We’ll never be able to see beyond that boundary, so for all intents and purposes, it’s the only universe we’ll ever interact with.

Beyond the Hubble Volume. We know with some certainty that there’s “more universe” out there beyond that boundary, though. Astronomers think space might be infinite, with “stuff” (energy, galaxies, etc.) distributed pretty much the same as it is in the observable universe. If it is, that has some seriously weird implications for what lies out there. Beyond the Hubble Volume you won’t just find more, different planets. You will eventually find every possible thing. In fact, cosmologists think that if you go far enough, you will find another Hubble Volume that is perfectly identical to ours. There’s another version of you out there mirroring your every action 10 to the 10^188 meters away. That may seem unlikely, but then, infinity is awfully infinite.

Dark Flow. In 2008, astronomers discovered something very strange and unexpected – galactic clusters were all streaming in the same direction at immense speed, over two million miles per hour. New observations in 2010 confirmed this phenomenon, known as Dark Flow. The movement defies all predictions about the distribution of mass throughout the universe after the Big Bang. One possible cause: massive structures outside the Hubble Volume exerting gravitational influence. This would mean that the structure of the infinite universe beyond our view is not uniform. As for the structures themselves, they could be literally anything, from aggregations of matter and energy on scales we can barely imagine to bizarre warps funneling gravitational forces from other universes.

Infinite Bubbles. Talking about things outside the Hubble Volume might be a bit of a cheat, since it’s still really the same universe, just a part of it we can’t see. It would have all the same physical laws and constants. In another version of the story, the post-Big Bang expansion of the universe caused “bubbles” to form in the structure of space. Each bubble is an area that stopped stretching along with the rest of space and formed its own universe, with its own laws. In this scenario, space is infinite, and each bubble is also infinite (because you can store an infinite number of infinities inside a single infinity). Even if you could somehow breach the boundary of our bubble, the space in between the bubbles is still expanding, so you’d never get to the next bubble no matter how fast you went.

Black Hole Spawning. A theory proposed by physicist Lee Smolin, known as the fecund universes theory, suggests that every black hole in our universe causes the formation of a new universe. Each universe will have slightly different physical laws than the forerunner universe. In this way, Smolin suggests a sort of natural selection for universes, as laws that lead to the frequent formation of black holes lead to the creation of more universes, while non-black hole forming universes “die out.” This theory has since been discounted (by Smolin himself and others).

Many Parallel Universes. There are tons of theories about parallel universes, but the most accepted one these days involves an evolution of the ideas of string theory to involve membranes that vibrate in other dimensions. It’s beyond the scope of this article to get too detailed about string or membrane theory, but the upshot of the whole thing is that these rippling membranes in the 11th dimension are whole other universes, and when the ripples slam into each other they form a new universe. The effects of the rippling motion help explain the observed distribution of matter in our universe. One of the weirdest elements of the theory is the idea that all the gravity we experience in our universe is actually leaking into it from another universe in another dimension (which explains why gravity here seems so weak compared to the other fundamental forces).

Sources:[x] [x] [x]

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