Heinrich Terahertz podcast: St Petersburg University astronomer tells about meteor showers, black holes, and space exploration
In the 15th episode of the popular science podcast of St Petersburg University "Heinrich Terahertz", Vakhit Shaidulin, Associate Professor in the Department of Celestial Mechanics at St Petersburg University, tells about what scientists know about black holes and exoplanets, how meteor showers are formed, and why stars do not actually fall.
Today, much is known about the closest cosmic bodies that are located inside the Solar system, said Vakhit Shaidulin, an astronomer from St Petersburg University. Scientists observe objects beyond its boundaries using optical means or electromagnetic waves.
What we know about space objects is underpinned by the model assumptions, which we then confirm or refute in the ways that are available to us. Today, we know very little about black holes, since they do not emit light, which means it is impossible to study them using conventional methods.
Vakhit Shaidulin, Associate Professor in the Department of Celestial Mechanics at St Petersburg University
"However, a lot of indirect data makes it possible to assume not only their presence, but also their location in outer space," explained Vakhit Shaidulin, Associate Professor in the Department of Celestial Mechanics at St Petersburg University.
For example, supermassive black holes are located in the centres of galaxies, including the Milky Way. Their manifestations are the most noticeable, but a number of indirect signs enable scientists to claim that there are a large number of black holes in the Universe.
Much better studied today are meteors, i.e. short-term flashes that occur when numerous small objects, such as comet fragments, burn up in the Earth’s atmosphere. These are the objects no larger than a grain of sand that pass through the Earth’s atmosphere at a fast speed (unavailable on Earth) and burn up in the Earth’s atmosphere.
When many meteors cross through and burn up in the Earth’s atmosphere, numerous flashes and visible light trails are formed. This is a meteor shower. Scientists from St Petersburg University have found out the age of the Geminids meteor shower. It originated 1,600 years ago from the collapse of a large cosmic body.
About 40,000 tons of meteorites, mostly the size of a speck of dust, fall to Earth every year, said Vakhit Shaidulin. It is unlikely that large bodies will fall onto the surface of the planet today, but you can never rule anything out.
"The orbits of such cosmic bodies, unlike the Earth’s orbit, can change, and quite dramatically. At some point, these orbits may intersect, and, with a high degree of probability, the meteorite will burn up in the atmosphere of our planet. However, really large space objects can fly and land on the Earth’s surface. To avoid this, it is necessary to constantly monitor and predict possible developments in the near future and prevent such collisions," said Vakhit Shaidulin.