“Experts don t know what it is.” A surprising fireball over Australia. “The meteor was half a kilometer in diameter.” Nonsense, nonsense, nonsense

For several days, more media have been reporting a "surprising fireball", "green and blue fireball", "mysterious fireball" that flew over Australia. Although the phenomenon itself was not unusual, the way the media described it shows how rarely we look at the sky and how much we do not know what we can see on it.

The meteor phenomenon was recorded using a mobile phone by Mitch Brune Port Headland in Australia.

In the film lasting a few seconds we see a long, bright streak illuminating the night sky over Australia. Such a trace is left behind by the meteoroid, which while traveling through the Solar System encountered an earthly atmosphere on its way. After entering the atmosphere, on the one hand, vapors escaping from the meteoroid surface begin to shine, and on the other, ionized atmosphere gases along the entire flight path.

What is a meteor?

Most often we see the meteor phenomenon in the form of the so-called shooting stars, short delicate lines that traverse the sky for a few seconds, and then disappear without a trace. Often, they are only responsible for the grains of sand that burn a moment after entering the Earth’s atmosphere. Already at an altitude of 300 km, the meteoroid begins to heat the denser air around it. After a while, at an altitude of about 120 km, an increasingly longer tail begins to form, formed of ions and electrons detached from the surface of the meteoroid, which at that time is already over 2000 ° C. Where does this temperature come from? It is enough to note that the speed of such a meteoroid entering the Earth’s atmosphere is from 12 to 72 km / s. Yes, for a second.

Statistics show that objects up to 10 m in diameter fall into the Earth’s atmosphere on average every hour. Objects with a diameter of 10 to 20 m fall into the atmosphere every 20-100 years, and larger than 100 meters – less than once every 1000 years. In short, the larger the less often. The last bigger car was the object that fell into the Earth’s atmosphere over Chelyabinsk in Russia. Scientists estimate that this meteoroid was 17 to 21 m in diameter. See the results below.

Above, you read a lot of numbers: the height at which the meteor phenomena arise, the size of the meteoroids or speed. At first glance they are technicalities, but it is worth realizing all this to know at least what order of magnitude is meant, so that afterwards such imps do not appear as, for example, the one in which in the morning information review we could hear that:

The meteor was visible in various parts of Australia. According to researchers, it had a diameter of about half a kilometer. NASA confirms that the asteroid was clearly visible, but there was no risk that it would hit the Earth because it was more than five million kilometers from our planet, a distance thirteen times longer than the distance between Earth and the Moon.

# MNIEŚMIESZY

Oh … For a good start to the day. TVN24 download this material because it is dilettante! Every sentence in this information is incorrect. The whole makes no sense !!

Published by Pulse of the Space Monday, June 15 2020

Fortunately, the information was quickly corrected by the TV station, but it is outrageous that nobody along the way did not make a noise. If the object entering the Earth’s atmosphere would have a diameter of 500 m, we would have a huge problem (it is worth noting that an object with a size of just 4 km would be able to arrange for us the future that dinosaurs got 65 million years ago). Similarly, if an object passes 5 million km from Earth (several times farther from Earth than the Moon), then even if it was and 100 km it would do nothing to us, because … the Moon is closer and it does not threaten us. What’s more, we wouldn’t even see him with the naked eye. And by the way the conventional border between the Earth’s atmosphere and space, the so-called Karman’s line is located 100 km above the Earth’s surface, not several million kilometers away.

Meteors you with us in abundance

There are several meteor swarms throughout the year. The most interesting of them – Perseida – we will be able to observe from July 17 to 24, when in the sky, from the constellation Perseus, we will be able to see even more than 100 meteors per hour, but I will write about it later.

From time to time, a space object larger than a grain of sand enters the Earth’s atmosphere, and then we can see the phenomenon of the so-called car. The car is nothing but a meteor with exceptionally high brightness, brighter than Venus in the evening or morning sky. An object with a size of a few to several centimeters can already lead to a car, nevertheless, it also depends on the chemical composition of such an object – some disintegrate quickly in the atmosphere, others last longer and brighten the sky for a long time; some burn in the atmosphere, others reach the very surface of the Earth, where we find them as meteorites .

So what has fallen in Australia?

Not known It’s hard to judge anything after recording from the phone. According to astronomers involved in analyzing data from the car stations, it could be an object the size of a basketball or a chair (Earth got from a chair – that would be the title). It is not known, however, whether the object completely burned in the atmosphere, or whether any of its remains have reached the surface of the Earth

Contrary to appearances, this is not a special event. According to estimates, nearly 300 tonnes of "space stones" fall to Earth every day. Most of them, however, no one can see – if you do not look 70 percent, the Earth’s surface is occupied by oceans, so if something above them enters the atmosphere, even something larger, then nobody will notice it. If a larger meteor or car falls into the atmosphere above the land, it can be seen by several, several dozen, several hundred or several thousand people who were just outside at the moment and looked more or less in the right direction. However, only the reports break into the media, the cases that were recorded by telephone, monitoring camera or camera in the car, hence the impression of the rarity of such phenomena. This time the phones were ready so we have a nice recording.

And that’s it.

"Experts don’t know what it is." A surprising fireball over Australia. "The meteor was half a kilometer in diameter." Nonsense, nonsense, nonsense

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