Monthly Archives: June 2018

Why is there zero gravity in space? By Michelle Thaller

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Michelle Thaller: Joshua, you ask a really great question, “Why is there no gravity in space?” I bet you’ve seen pictures of the astronauts up in the space station and they’re floating around as if there’s no gravity at all. This is actually a really interesting misconception about what’s going on with the astronauts. And it gets to one of my favorite questions in all of astronomy, and that is: what is an orbit? What’s happening when astronauts are orbiting the Earth? And why does it appear like there’s no gravity in space?

So, to talk about why this is kind of a misconception, the astronauts are about 200 miles above the surface of the Earth in the space station; the space station orbits around us about once every 90 minutes. It’s not that they’re so far away from the Earth that there’s no gravity—in fact, if you built a skyscraper that was 200 miles tall and you were up on one of those top floors you might weigh a tiny little bit less, but you probably weigh at least about 80 percent what you normally would. You’re really not that much farther away from the Earth. So it’s not that they’re weightless because they’re in space and far away from the Earth, they’re actually close enough to the Earth to feel the gravitational pull of the Earth itself. So what’s going on? Why are they floating around?

Well, this is what an orbit really is. We have to get spacecraft going very, very fast to put them into orbit. That’s why we put them on rockets. Rockets launch spacecraft and get them going very, very fast, and if you’re in orbit where the space station is, you’re traveling at about 17,000 miles an hour.

Now, what happens to those astronauts is that they’re going very, very fast but they’re actually freely falling towards the Earth. The Earth has gravity, and that gravity is pulling them down just the same as what would happen as if you dropped a ball. If you dropped a ball it would fall to the floor. The same thing is happening to the astronauts; they are falling towards the surface of the Earth.

But here’s a cool thing: they’re going so fast they keep missing the Earth as they fall. And that’s the definition of an orbit.

Now think about it this way: I talked about dropping a ball and the ball just falls straight down; what would happen if I put the ball in a little cannon and shot it out? The ball would start to drop towards the Earth the minute it left the cannon, but the cannon has given it some velocity, and so the ball might go a hundred yards, right? It might actually go a hundred yards before it fell because the cannon gave it that velocity.

Now, let’s take an even bigger cannon, let’s take a huge cannon that can shoot things many, many miles. So you shoot the ball out, the ball is still falling freely towards the Earth all the time, but now it goes farther because you’ve given it more velocity. And maybe with a really big cannon, you can shoot a ball a hundred miles.

What about with a rocket? With a rocket, you could get something going so fast, up to 17,000 miles an hour, that as it fell freely towards Earth, Earth would keep curving away under it and it would keep missing it.

That’s what an orbit is, and that’s why you need a rocket to get into orbit. You need to get yourself going so fast that, as you fall back towards Earth, you keep missing it.

So the astronauts are not weightless because there’s no gravity in space; the astronauts are falling the same way a skydiver is falling freely through space, it’s just that they’re going so fast they keep missing the Earth.

They are all the time falling towards the Earth going fast enough that they keep missing it.

Everything that’s in orbit around anything else is doing the same thing. Right now you and I are falling freely towards the sun, but the Earth is moving, actually at about 30,000 miles an hour, and we keep missing the sun as we go around it, and that means we’re in orbit around the sun.

The moon is in orbit around the Earth. It’s falling towards the Earth, it’s just traveling so fast it keeps missing it. You’ve asked an excellent question. Everything in space that is orbiting is freely falling under gravity, it’s just going too fast to ever hit anything.

http://bigthink.com/videos/michelle-thaller-why-is-there-zero-gravity-in-space?utm_source=Daily+Newsletter&utm_campaign=e9898486a6-EMAIL_CAMPAIGN_2018_06_07&utm_medium=email&utm_term=0_45b26faecc-e9898486a6-43656993

“Post-America World & Post-America, America” By F. Sheikh

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After WWII, two new super powers emerged, United States of America and Soviet Union. America took a central stage in world politics as well as in world economy. Britain and other colonial powers were forced out of their colonial lands. American expanded its influence in many of those countries. America’s Marshal plan for war ridden Europe expanded its influence in Western Europe. Soviet Union took Eastern Europe under its fold and started to compete with America for its own influence in other countries. This gave us cold war, arms race, proxy wars and ideological war around the globe. America supported even dictators and monarch, especially in the Middle East, for its influence and economic interests.

America became a military giant and at the same time an economic powerhouse attracting talent from around the globe. Soviet Union tried to match America’s military might and dominance, but it sorely lacked economic development and disintegrated in 1991, leaving one super power standing-United States of America.

Despite America’s record of supporting favorite dictators, toppling unfriendly regimes and brutal ideological wars, it was still seen in the world as a symbol of human aspirations of liberty, success, and individual prosperity. Overall America projected itself as a force of good, democratic values, and morals; and it considered itself guardian of those values in the world and at home.

All this perception started to change after America’s fierce and revengeful response to brutal 9/11 attack. In anger and short-sightedness, it trampled on the very same values and ideals, both at home and abroad, which it wore as a badge of honor and national identity. It adopted torture forbidden by Geneva Convention, opened Rendition Torture Centers abroad, locked up prisoners, including some innocents, for years at Guantanamo Bay without Habeas corpus, abused prisoners at Abu Gharib and in Afghanistan, and violated civil liberties at home with Patriot Act. Cities were bombed to stone ages with thousands of innocent civilians killed in Afghanistan and Iraq.  America eroded its leadership in the world as guardian and leader of moral, liberal, and democratic values.

President Obama tried to reverse this erosion by half measures, but it has taken its roots. Anti-terrorism evolved into an industry requiring full attention and resources at the expense of other priorities. United States forced other countries to adopt similar anti-terrorist measures and allocate essential resources. Tyrants and oppressive regimes further strengthen their grip on power by utilizing anti-terrorist excuses. Meanwhile globalization created extreme inequality that went unnoticed and unattended by the mainstream political parties. Eroded values and inequality, a fertile ground for populous parties and demagogue leaders, gave us Donald Trump and populous leaders in other countries.

Donald Trump destroyed, within a short time, last vestiges of America’s leadership and moral standing in the world and is isolating itself from rest of the world. We are still superior economic and military power, but we are no longer the leader. It is a post-America world unfolding in front of us. Western Europe is adrift, while China is flexing its newfound economic muscle. New technology, including social media, has provided new tools to adversaries that can sow the seeds of discontent and factionalism without much investment. America lost its leadership at a crucial moment when it was needed the most to create strong global norms and rules to prevent the abuses of new technology which has the potential of great benefits but at the same time potential of unleashing destructive forces. This leadership was critical when the global and domestic infrastructure in every sphere of life depends on new technology.

When you are a world leader, you are under pressure to perform better in every aspect, both abroad and at home. The world holds you at a higher standard. When the leadership standing is eroded, performance deteriorates. It is a vicious cycle. When your own expectations are low, and others also expect low from you, it is hard to improve performance.  In a recent article in Washington Post, Ben Guarino writes that some top researchers from ivy league institutions are moving to China for lack of funding and visa restrictions. China is offering them all the resources needed and better monetary benefits. China is attracting talent from the rest of the world also that was our hallmark and lifeline.

America itself is a post-America country now. American ideals, values and patriotism take a back seat to personal and political party interests. Our political leaders are no different from third world country leaders who do not hesitate to undermine established national institutions of democracy for personal interests. Our business corporations are richer than country, but no longer feel obligation to the country that provided them resources to get rich.

Can it be reversed? Off course, but first we must restore our ideals, morals and stop the slide. It will get harder with every passing day, especially with incompetent and shortsighted leadership.