The Drake Equation:

The Drake Equation was created in 1961, by Frank Drake.
(N=R* × f p × n e × f l × f i × f c × L).
This was his attempt to estimate the number of other intelligent life forms in the Universe.
His original reason for creating this equation was not only to figure out how many other planets have life, but, also to promote Scientific discussion about extraterrestrial life in the Cosmos.
N= The number of intelligent life forms in the Milky Way Galaxy with advanced technology, who would be able to communicate with us.
(For example, they would have a radio telescope which can send and receive messages to and from other planets far away.)
R= The rate at which new stars form in our Galaxy.
Fp= The fraction of stars with planets.
Ne= Number of planets in each solar system with an environment that could support life.
Fe= Fraction of planets that could support life on which life actually appears.
Fi= The fraction of life-bearing planets that actually have intelligent life.
Fc= The fraction of civilizations that release detectable signs of their existence into space.
L= Length of time such civilizations have been releasing detectable signals into space.
This equation is only a "guesstimate" (Combination of a guess and an estimate) of how many planets in ONLY THE MILKY WAY GALAXY would possibly have intelligent life with whom we could possibly communicate.
The Milky Way is the name of the galaxy in which we live.
Each Scientist that has used this equation has used different numbers. It is just each person's individual guesstimate of how many planets in our galaxy might have intelligent life.
By using different numbers, each Scientist has come up with different answers. Some Scientists have estimated: 1,000 planets. But the most common answers have been around 2 or 3. With Earth being one of them.
Anyway, you take the number that you come up with for the amount of planets in the Milky Way and guess that more than likely, most other galaxies that support life will have approximately the same number of planets with intelligent life. 
There are over 1 Trillion galaxies that Scientists have observed in the Universe. However, that to is a guesstimate. Because nobody can count to 1 Trillion.
I would guess that about half of all galaxies don't have any life at all. That leaves 500 Billion galaxies that might have life. Of those, only half of them will have a planet or Two with intelligent life. Leaving us with 250 Billion galaxies. Then, only half of those will be sending detectable signals into space. That is 125 Billion. 
Galaxies only contain a small amount of everything that is in the Universe, around One percent (1%)! Everything else is just in open space. This fact was not taken into consideration in the equation. So, there could be Octillions of more planets in open space that are not in a galaxy.
With my figures, each galaxy with intelligent life would have Two planets with life forms who are trying to communicate with us or aliens on other planets. My guess would be about:
125 Billion galaxies times Two planets in each with intelligent life, which equals 
250 Billion. Plus all the planets with intelligent life in open space:
1,000,000,000,000,000,000,000,000,000,(Octillion) more planets!
However, we will never know for certain how many other alien life forms are out there.
Radio signals travel at the speed of light: 186,282 Miles per Second. 5.878 Trillion Miles/year.
The nearest star is "Proxima Centauri" is about 4.2 light years away. It is part of the Alpha Centauri star system.
Most other stars are hundreds, thousands or even Millions or Billions of light years away.
Scientists on Earth have been sending signals to other stars and other galaxies for about 60 years as of this writing (August, 2019). That means our signals have only traveled a maximum of 60 light years. They have gone way past Alpha Centauri. But, all radio signals from Earth will take over 2,537,497 Million years to get to our nearest, large galaxy, the Andromeda Galaxy! 
More than likely, no intelligent, alien life forms will ever receive our radio signals in your lifetime. 
If a signal from Earth takes 1,000 years to get to a planet and someone can interpret it, figure out where it came from and send a signal back in the exact same direction that it came from, their signal will take 1,000 years to get back to Earth.
They can only receive, read the signal and send a signal back IF they have a Radio Telescope or something similar.

Black holes in the center of the Milky Way Galaxy.

Scientists have known for a long time that there's a Supermassive Black hole in the center of the Milky Way Galaxy. But, now they've found a lot more small black holes and they guesstimate that there might be as many as 10,000 more small black holes in the center of the Milky Way Galaxy.
The way most most Supermassive Black holes form is by "eating" other black holes, stars and other things. Everything that the black hole consumes adds more mass to it and the black hole grows. The more it eats,  the bigger the black hole becomes. Most black holes start out as small ones. Then they suck things in it and they become bigger.
The way they form in the first place is:
A giant star runs out of Hydrogen and other forms of fuel. It collapses and what's left over is a black disk that has an immeasurable amount of mass. In fact, according to Einstein, a black hole might have an infinite amount of mass. However,  I find that hard to believe, because it sounds impossible for anything to literally have infinite mass.
The Sun is a Medium star. It doesn’t have enough mass to form a black hole. Scientists measure other stars, black holes and other really large objects in space with.   "Solar. Masses". One solar mass is the mass of the Sun.
In order to form a black hole, a star has to be at least 5 solar masses.
There are a few black holes that Scientists have found which they think are Millions or Billions of solar masses. These are called: Supermassive Black holes. There is one in the center of every spiral galaxy, including the Milky way.
The gravity from these Supermassive black holes helps hold the galaxies together.
Scientists are not sure exactly how Supermassive black holes form. However, one reason might be that it could of consumed Thousands of other black holes and planets and kept getting bigger.
The gravity from a black hole is so strong that almost nothing can escape from it. Even if something traveled at the speed of light, it would not be able to escape from the gravitational pull of a black hole. That is why they are hard for Scientists to find.
However,  Stephen Hawking discovered a type of radiation that does manage to escape from black holes. Since he discovered it, this radiation was named: Hawking radiation. Astronomers need special, X-ray telescopes to see it.
This technology is so new, that until recently, nobody had ever actually seen a black hole. They knew they existed, because they could see stars, planets and other things getting sucked into them. Hopefully, with the newer, X-ray telescopes, Scientists will actually be able to get a picture of a black hole for the first time ever! Astronomers have been talking about trying to do that this year (2018).

https://www.sbs.com.au/news/dozen-black-holes-discovered-at-the-milky-way-centre