{"id":2088,"date":"2012-08-03T00:06:37","date_gmt":"2012-08-03T07:06:37","guid":{"rendered":"http:\/\/nettelhorst.com\/blog1\/?p=2088"},"modified":"2012-08-03T00:06:37","modified_gmt":"2012-08-03T07:06:37","slug":"profound-emptiness","status":"publish","type":"post","link":"https:\/\/nettelhorst.com\/blog1\/2012\/08\/03\/profound-emptiness\/","title":{"rendered":"Profound Emptiness"},"content":{"rendered":"

\tIn The Hitchhiker\u2019s Guide to the Galaxy<\/a><\/em> Douglas Adams wrote \u201cSpace is big. You just won\u2019t believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it\u2019s a long way down the road to the chemist\u2019s, but that\u2019s just peanuts to space.\u201d One of the hardest things for humans to comprehend is the vast amount of nothing that is most of reality as we know it. Overwhelmingly most of reality, in fact.<\/p>\n

\tOn January 19, 2006, the New Horizons probe was launched toward Pluto. It left Earth with the fastest launch speed ever recorded for a human-made object, at about 36,000 miles per hour or about 10 miles per second. At that speed, it could fly from Los Angeles to New York City in a little more than four minutes. About eight hours after launch, it had sped past the orbit of the moon, traversing a distance that had taken the Apollo astronauts three days to cross. It passed the orbit of Mars on April 7, 2006, barely three months after liftoff. On February 28, 2007 New Horizons went past Jupiter. It passed the orbit of Saturn on June 8, 2008. It passed the orbit of Uranus on March 18, 2011.<\/p>\n

\tAnd how close is New Horizons to reaching Pluto? It is currently about 23 AU from Earth and still has about 8 and a half AU to go<\/a> (one AU–astronomical unit–is about 93 million miles, the distance from the sun to the Earth). It won\u2019t reach Pluto until July 14, 2015.<\/p>\n

\tOur solar system is mostly empty space. Even those regions that are considered crowded\u2014for instance the asteroid belt\u2014are really very empty. Despite the images we have from numberless science fiction shows of spaceships facing the asteroid belt and dodging enormous rocks in space and surviving only due to the incredible skill of the astronaut pilot, the reality is radically different. On any trip through the asteroid belt, it\u2019s improbable that you\u2019d even catch a glimpse of a single asteroid. A significant number of spaceships, including New Horizons, have now passed through the asteroid belt in the years since space travel began, all without any difficulty at all. There were no tricky maneuvers necessary, and no demonstration of exceptional piloting skill. Traveling through the asteroid belt is like a trip across the back roads of Nevada, only more so: a trip through emptiness, just like the rest of the solar system.<\/p>\n

\tAnd the emptiness of our solar system is nothing compared to the emptiness between the stars.<\/p>\n

\tThe Milky Way Galaxy has about 400 billion stars in it. Our nearest spiral neighbor, the Andromeda Galaxy is a fuzzy spot in the sky that you can see in the evening if you look toward the northeast. It\u2019s about 2.5 million light years away, and contains about 1 trillion stars. The Milky Way and the Andromeda Galaxy are racing toward each other at around 87 miles per second. They will suffer an inevitable collision in about 4.5 billion years. That\u2019s right. Traveling at a speed that would take you from Los Angeles to New York in 28 seconds, it will take these two galaxies billions of years to meet up in a train wreck to beat all train wrecks.<\/p>\n

\tExcept\u2014galaxies, for all their grandeur and size, and as packed as they might appear in pictures, are still mostly empty space. When they smash together in the future, a collision that itself will take about a billion years\u2014not one star is likely to ever touch any other star. In any collision between galaxies, it\u2019s profoundly improbable that any two stars will smash into each other. Consider: the closest star to Earth is over four light years away, close to the average distance between stars in either galaxy. And in the end, the two galaxies will become one.<\/p>\n

\tThere will be effects from the collision, of course: stars will move, a few may be tossed out of the galaxy altogether by the gravitational interactions among them. In fact, there\u2019s about a fifty percent chance that our own solar system will be flung into intergalactic space. But chances are, no actual collisions between any of the stars\u2014or their planets\u2014will occur.<\/p>\n

\tSpace is empty\u2014an emptiness beyond our ability to comprehend. Even so, that our galaxy will collide with the Andromeda Galaxy\u2014or any galaxy\u2014 is actually more likely than a collision between stars. How come? Because of the vast size of the galaxies. The distance between neighboring stars is approximately equal to ten million times the diameter of a star. By contrast, the distance between galaxies is approximately only twenty times the diameter of a galaxy. So as enormous as the distance between galaxies is in absolute terms, the relative distance is actually quite close. Therefore, galaxies collide far more often than stars.<\/p>\n

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In The Hitchhiker\u2019s Guide to the Galaxy Douglas Adams wrote \u201cSpace is big. You just won\u2019t believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it\u2019s a long way down the road to the chemist\u2019s, but … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"_s2mail":"yes"},"categories":[4,23],"tags":[],"_links":{"self":[{"href":"https:\/\/nettelhorst.com\/blog1\/wp-json\/wp\/v2\/posts\/2088"}],"collection":[{"href":"https:\/\/nettelhorst.com\/blog1\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/nettelhorst.com\/blog1\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/nettelhorst.com\/blog1\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/nettelhorst.com\/blog1\/wp-json\/wp\/v2\/comments?post=2088"}],"version-history":[{"count":2,"href":"https:\/\/nettelhorst.com\/blog1\/wp-json\/wp\/v2\/posts\/2088\/revisions"}],"predecessor-version":[{"id":2090,"href":"https:\/\/nettelhorst.com\/blog1\/wp-json\/wp\/v2\/posts\/2088\/revisions\/2090"}],"wp:attachment":[{"href":"https:\/\/nettelhorst.com\/blog1\/wp-json\/wp\/v2\/media?parent=2088"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nettelhorst.com\/blog1\/wp-json\/wp\/v2\/categories?post=2088"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nettelhorst.com\/blog1\/wp-json\/wp\/v2\/tags?post=2088"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}