The First Spacewalker: Alexei Leonov
Alexei Arkhipovich Leonov was a Soviet and Russian cosmonaut, Air Force major general, writer, and artist. On 18 March 1965, he became the first person to conduct a spacewalk, exiting the capsule during the Voskhod 2 mission for 12 minutes and 9 seconds.
In July 1975, Leonov commanded the Soyuz capsule in the Apollo-Soyuz mission, which docked in space for two days with an American Apollo capsule.
His walk in space was originally to have taken place on the Voskhod 1 mission, but this was cancelled, and the historic event happened on the Voskhod 2 flight instead. Leonov was connected to the craft by a 4.8-metre (16 ft) tether during his space walk. He had spent eighteen months undergoing weightlessness training for the mission.
At the end of the spacewalk, Leonov’s spacesuit had inflated in the vacuum of space to the point where he could not re-enter the airlock. He opened a valve to allow some of the suit’s pressure to bleed off and was barely able to get back inside the capsule.
While on the mission, Leonov drew a small sketch of an orbital sunrise, producing the first ever work of art made in outer space. We will feature this work in our art column this week.
But first, let’s take a look at the magical structure of black holes.
Inescapable Black Holes
Black holes are objects with such extreme density that they can even capture light if they come close, due to their extraordinarily strong gravitational pull. With these features, we can say that they are the strangest and most interesting objects in space. The term “Black Hole” was coined by American astronomer John Wheeler in 1967. Then, in 1971, the first black hole was discovered. Black holes have incredibly large masses, but are located in a small area because they are extremely dense. There is a large gravitational force due to the mass-gravity relationship. According to the laws of classical physics, nothing can escape from it. It can even trap light inside. Such a strong gravity creates an observational problem when it comes to black holes. Astronomers cannot see black holes the way they can see stars and other objects in space. Instead, they must rely on radiation when making observations.
Black holes have three layers: outer event horizon, inner event horizon, and singularity.
The event horizon of a black hole is the boundary around the black hole where light loses its ability to escape. Once a particle crosses the event horizon it cannot be separated. Gravity is constant along the event horizon. The inner region is known as the center of the singularity. The mass of the black hole is concentrated here.
In classical physics, nothing can escape a black hole. However, there may be changes when quantum mechanics is added to the equation.
Types of Black Holes
There are three types of black holes. These; stellar source black holes, supermassive black holes and intermediate black holes.
- Star Source Black HolesWhen a star reaches the end of its life, it destroys itself. When small stars four times the size of the Sun end their lives, the new core becomes a white dwarf or neutron star. Massive stars, on the other hand, can form star-derived black holes.
Black holes formed by the collapse of stars are extremely dense. Under the influence of extraordinary gravitational forces, black holes increase their size by drawing in dust and gas from nearby galaxies.
- Massive Black HolesAlthough there are many small-sized black holes in space, massive black holes are more effective. Supermassive black holes are billions of times the mass of the Sun.
The formation of supermassive black holes is divided into three ways. These include:
- Such black holes are found at the centers of many galaxies, including the Milky Way Galaxy. In the center, they can absorb enough material to increase their size and reach gigantic sizes.
- They can be formed by the merger of hundreds or thousands of black holes.
- They can form when large gas clouds and a group of stars collapse together.
- Intermediate Black HolesAstronomers thought black holes were only small or large in size. However, recent research has shed light on the possibility of medium-sized black holes existing. Such black holes can be formed by chain collisions of stars in a star cluster.
In 2014, astronomers discovered the existence of an intermediate-mass black hole in a spiral galaxy arm. Thus, their existence went beyond theory.
This Week in Our Art Corner
Leonov was awarded a Hero of the Soviet Union distinction after becoming the first person to walk in space in 1965. On the same mission, Leonov, an enthusiastic and talented artist, drew the view of the sunrise. Given his circumstances, it was astonishing. “Imagine,” said Natalia Sidlina, curator of Cosmonauts: Birth of the Space Age, “you are fully dressed in your warmest clothes, then you have skiing gear on top of that, a motorbike helmet and you are strapped to a chair in a tiny circular spacecraft, which is orbiting the Earth at a very high speed.” Then there is the fact that the craft was designed for one person but contained two. And the problem of using pencils and paper in zero gravity. “You can imagine it being a bit of a nightmare … but he wanted to stop the time and share this moment with other people,” Sidlina added. The pencils were adapted to deal with weightlessness – though not in a particularly hi-tech way. A rubber wristband was attached to the packet and individual threads to each of the pencils.