A fireball appeared in Beijing! Can you pick up a meteorite?

In the early morning of March 27, a rare scene occurred in Beijing: a blue ball of light with a "tail flame" crossed the night sky, flashed twice in just a few seconds, and instantly illuminated the sky.

Li Liang, a popular science expert at the Beijing Planetarium, explained that this "light ball" might be a fireball , which is rare because it appears for a long time and is very bright. Kou Wen, a senior engineer at the Beijing Planetarium, also said that meteorites might fall to the ground during the fireball's fragmentation.

Immediately, the topics #A super fireball streaked across the sky over Beijing# #Super fireball streaked across the night sky over Beijing# became a hot search, sparking discussion among netizens.

Source: Weibo

So, what is a fireball and why does its appearance bring meteorites?

1

What is a fireball?

Fireball is a type of meteor phenomenon, which refers to an astronomical phenomenon caused by the friction between a meteor with a diameter of more than 1 meter and the ablation and air explosion of a meteor when it enters the atmosphere. Fireballs are usually extremely bright, like a giant shining fire dragon across the sky, or make a "rustling" sound, or explode with a roar. A very small number of fireballs with very high brightness can be seen even in the daytime.

Fireballs are one of the most amazing astronomical phenomena in the sky. According to the regulations of the Fireball Data Center of the International Meteor Organization, all meteors that are brighter than -3 magnitude after being corrected for zenith position are defined as fireballs.

Fireball

Source: Wikipedia

In the news at the beginning of the article, the fireball that appeared in Beijing was blue. In fact, **fireballs come in many colors, including red, blue, purple , etc. **The causes of the generation and change of these colors are relatively complex, mainly related to the material composition of the meteoroid and the composition of the atmosphere.

For example, if the meteoroid material contains sodium, the meteoroid will appear yellow; if it contains magnesium, the meteoroid will appear white-blue; if it contains nickel, it will appear green; and the common red meteoroids are mainly due to the light produced by nitrogen and oxygen in the atmospheric components.

2

Why do fireballs produce meteorites?

After a meteoroid enters the Earth, it begins to burn due to friction with the atmosphere. Smaller ones will burn up during their descent, while larger ones will further explode and break into pieces in the air, with the resulting fragments falling to the Earth's surface. These are called "meteorites."

For example, the fireball that appeared in Songyuan, Jilin in 2019. At that time, professionals and amateur enthusiasts calculated the landing trajectory of the fireball. They searched the "area where meteorites might appear" for several days, but no meteorites were found. Therefore, the Songyuan fireball may have been a meteoroid that was completely burned out before landing on the surface.

Hoba meteorite weighs 60 tons

Source: Wikipedia

Meteorites are divided into three types according to their materials: stony meteorites (main components: silicate minerals), iron meteorites (main components: iron and nickel), and stony-iron meteorites (main components: a mixture of iron and silicates).

The type of meteorite dropped by the Beijing fireball this time needs to be determined through subsequent testing and classification by professionals.

When a meteorite hits the ground, it forms a circular depression, also known as a "penetration hole". The size of meteorite craters varies greatly, some are very small, only a dozen centimeters in diameter, and some can reach several meters or even hundreds of meters. For example, the Shanghai Planetarium has exhibited the "Mangui" meteorite crater formed in 2018, which has a diameter of only 13 centimeters.

Crater formation process

Source: Wikipedia

Complete meteorite craters will be recovered and preserved because they can fully prove the occurrence of meteorite landing events. At the same time, they can also help scientists conduct further research on the landing trajectory and speed of fireballs, and have certain scientific research value.

In addition, regarding meteorites, some people stay away from them, thinking that they have radiation and will harm the body. In fact, the age of meteorites is generally more than 4.5 billion years, and many of the radioactive elements in them have decayed away, so they are not very harmful to the human body, so there is no need to worry too much.

3

Differences between fireballs and meteor showers

Fireballs and meteor showers are both types of meteors.

The "meteoroids" that form meteor showers are tiny particles that are volatilized from comets or asteroids after being affected by the solar wind. Their diameters range from a few millimeters to a few microns.

They orbit the sun along the same orbit, and there is a space that intersects with the earth's orbit. At a certain time every year, when the earth passes near these particles, they rush into the earth's atmosphere at almost the same speed and direction, forming the phenomenon of "meteor showers".

In most years, the main meteor shower is the Perseids in mid-August, while the most spectacular meteor shower is the Leonids , which peak around mid-November.

Source: Liu Peng, "Formation and Observation of Meteor Showers", Journal of Mianyang Normal University, 2003

Fireballs are actually not uncommon. In recent years, with the widespread deployment of various surveillance cameras, people have more and more opportunities to see fireballs.

Many people are very curious about these "extraterrestrial visitors". "Things are precious because they are rare", and some people are also keen on collecting meteorites. The value of the collection is affected by many factors, such as the type of meteorite, completeness, scientific research value, aesthetic level, etc.

For example, a meteorite named Almahata Sitta discovered in Sudan is the first meteorite sample from asteroid 2008 TC3 discovered by humans, and its price is very high.

Almahata Sitta meteorite was discovered

Source: Wikipedia

In general, the appearance of fireballs provides scientists on Earth with an opportunity to get close to planetary bodies. Through the meteorites dropped by these fireballs, we can study and obtain information about various asteroids and even the original nebula of the solar system, which is of great significance to the mileage of human space exploration.

For ordinary people, while we appreciate the beautiful meteors, we can also learn more about them, which can bring us closer to the vast universe. Next time you see a meteor, don't just make a wish.