Rain is common in life. Since human beings entered the Industrial Revolution, due to air pollution, they have sometimes heard news reports such as black rain, yellow rain, and green rain.
But have you ever heard of red rain falling from the sky? Probably, first impression: this is definitely caused by air pollution. However, if these red rains are composed of red cells, then this rain is a blood rain.
In 2001, in the southern Indian state of Kerala, it rained for more than two months. The rain was as red as blood, and the scene was terrifying. Bizarrely, the red rain range was limited to a few square kilometers, and after two months, it did not spread.
A few days before the red moon, local people used to hear a huge explosion, and many houses were squeaked by the earthquake. One can be sure that it was not thunder, but a special kind of huge explosion.
Could it be that a mysterious extraterrestrial object passed through the atmosphere and just landed here and exploded? What are these red rains, and will they be alien microbes?
At first, physicists in India suspected that the red rain particles were red sand, probably from which desert it had drifted. Because in 1968, there was red rain in the United Kingdom, and later tested, these red rain particles are sand particles, they come from the Sahara Desert, by a high-pressure air pump to bring over.
But when Indian biologists tested it, the red rain grain hypothesis was quickly overturned. Because, through biological tests and electron microscopy, these red particles are similar to biological cells.
They have cell walls, amino acids, carbon, oxygen, sodium, iron and other substances inside, and the composition structure is very similar to that of biological cells. The only strange thing is that there is no nucleus in the cell, and the DNA inside the cell cannot be found.
This shows that the red rain particles are certainly not sand particles. Moreover, the scope of the red rain's descent is very strange, it has been over Kerala for two months, no matter how the weather and wind direction change, it can never be taken away.
This shows that the red rain is not swept by strong winds and rain. Its formation is either formed by local mysterious species, or it is formed by alien mysterious species left behind.
Combined with the explosions heard by locals, many scientists have proposed the hypothesis of "extraterrestrial beings" . The explosion may be caused by alien meteors passing through the atmosphere, and when they reach the ground, they explode into many tiny particles and microorganisms. As the local climate rains, these microbial cells fall with the rain.
This hypothesis, while bizarre, quickly caused a heated debate. Opponents argue that "extraterrestrial life" is nonsense and does not exist at all. However, there are also many supporters.
Many proponents believe that the red rain event is the answer to the origin of life on Earth. The origin of life on Earth is likely to be different microorganisms from space.
The origin of life on Earth has always been a mystery. Although there is a Darwinian theory of evolution, where did the original protocells come from?
The Earth has been around for 4.5 billion years, but there is plenty of evidence that life didn't exist in the first 3.9 billion years. At 3.9 billion years ago, the Earth suffered a violent impact. In the 50,000 years after this impact, life suddenly flourished, and the speed of evolution was incredible. Therefore, it is suspected that the original cells came from outer space.
Although many people believe that the earth is the only place in the universe where life exists. But now many scientific experiments have also proved that microorganisms can withstand extreme cold, dry and other environments. Therefore, primitive cellular organisms may have survived before they reached Earth.
In 1996, a meteorite from Mars numbered "ALH84001" arrived on Earth, which once caused a boom in earth's search for extraterrestrial life. Because scientists found that on the surface of Martian meteorites, there are microbial fossils.
However, some people have proposed another hypothesis, perhaps these red rain particles still come from the earth.
The first is that pollen cells say that red rain particles are considered to be a fungal spore, or pollen and certain fine algae.
This hypothesis was quickly rejected. These plant granule cells all have nuclei, so why don't they have nuclei in the red rain particles? Plant cells generally have chloroplasts needed for photosynthesis, but they are not found. In addition, under the microscope, it was shown that no chitin was found in the cell wall of the red rain particles, which is found in the cells of ordinary algae plants.
Since it is not a plant cell, will it be an animal red blood cell?
Some biologists say these red rain granules are very close to the size of red blood cells in mammals. What's more, mammalian red blood cells do not also happen to contain nuclei.
And that's another horrible hypothesis? According to more than two months of rainfall, where did so much mammal blood come from?
Could it be a bird or a bat flying in the sky? There are indeed a lot of bats in southern India, with thousands of bats migrating every year.
But if it's the red blood cells of bats, where do their bodies go? Moreover, the survival of red blood cells in mammals is very short, and they may only be able to remain active for a few minutes without leaving the internal environment.
In 2006, red rain particles were sent to the Wicknama Laboratory in the United Kingdom for testing. After testing, scientists found another amazing phenomenon.
They put the red rain particles into some conventional cell culture solution, and found that the red rain particles actually divided. That is to say, they are also active and can even replicate themselves.
Therefore, some people believe that this is not an ordinary plant cell or animal red blood cell at all, but a mysterious biological cell.
To this day, the exact answer to the mystery of India's red rain remains unannounced.
Intriguingly, many of the biologists involved in the study at that time also kept the matter secret, perhaps they still did not find the exact answer, or they may have found something, but it was stored as a file seal.