What were the odds?

The following video should be a reminder to think critically when watching the news. Just because someone on TV said it doesn't make it true. Always be sure to check the original source of facts quoted in television and radio shows.

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There's some fear mongering before the story even starts: "...a hunk of metal that could wreck havoc when it hits. Is it headed towards your neighborhood?" Scared? Don't be, because this news story should be the absolute least of your worries.

The first big mistake comes when Dan Harris claims that most of the satellite will burn up in "the scorching hot ring that surrounds the Earth." Most of the satellite will, indeed, burn up, but not because of any scorching hot ring. The real cause of the satellite's incineration will be friction with gas molecules in the Earth's atmosphere as the satellite smashes into those molecules at incredible speed. While individual molecules in the upper atmosphere tend to have more energy than their counterparts closer to the surface, there are far fewer molecules at higher altitudes, resulting in much lower temperatures. There's no scorching ring around the earth. Besides, wouldn't a giant scorching ring that encircles the entire globe seem like an obvious culprit behind climate change? I would have expected to hear about such a super-hot ring from scientists and politicians before now.

The next major error comes when Dan reports the odds of you getting struck by one of the 26 sattelite pieces "as you're walking down the street." He claims that NASA projects the odds of you getting hit are 1 in 3,200. Dan follows this up by stating that the odds of you being in a car accident in the next 2 years are 1 in 5,244. If these statements are accurate, it follows that each of us is over one and a half times as likely to be struck by one of the 26 satellite pieces as to be in a car accident over the course of the next 2 years. If you haven't raised an eyebrow yet, now's the time. There are only 26 satellite pieces to cover the entire world, and I'm willing to bet that there will be more than 26 car accidents world-wide over the next 2 years.

So where'd ABC news get that "1 in 3,200" figure? NASA reported those odds to reflect the probability that someone, somewhere on the planet would be hit. The key difference from the ABC news report is that those odds are for any person getting hit, as opposed to you being hit. If we multiply the probabilities (which I'm going to assume are independent) that a satellite piece hits someone on the globe (1/3,200) and that the unlucky individual out of the whole population happens to be you (1/6,960,000,000)... the odds that you will be hit by one of the satellite pieces are around 1 in 22,272,000,000,000. Still scared? I'm not.

The satellite pieces have landed in Canada, and nobody is reported to be hurt. Based on Dan Harris' reported statistic, we should have expected about 96,000 people to be struck in the US alone (population about 307,000,000). Remember, there are only 26 pieces that would have been responsible for all those people getting struck. Hopefully, ABC news will learn from this error, and we should all remember to check our facts before making significant claims.