Why does the moon always show us the same face?

Wherever you live, and whenever you look at it, the moon always shows the same face.

This is due to a phenomenon known as synchronous rotation. This means that the Moon rotates on itself and on the Earth at the same speed.

Specifically, it takes the Moon about 27.32 days to complete one rotation about itself and around the Earth.

Where does the Solar System end?

One light year away from the Sun, is the Oort Cloud.

The Oort Cloud is a spherical cloud of transneptunian objects located at the edge of the gravitational influence of the Sun.

Beyond this region, the gravity exerted by the Sun is not sufficient to make something orbit it, so it is considered the end of the Solar System.

How to study astronomy?

It depends on the country you live in. In some educational systems, astronomy is a graduate course for which you must first have studied a career in physics or mathematics.

You could also choose a telescope to start studying alone the astronomy.

The best thing you can do is to find out what it’s like in your country and, in any case, get your hands on the math as soon as possible.

What's the nearest star?

If we talk about the closest star to Earth, the answer is obvious: the Sun.

But if the question is which star is the closest to the Solar System, we are certainly talking about Proxima Centauri, a star located 4.22 light years away in the Alpha Centauri system.

And if you want to know which is the furthest star you can see at night, click here.

What's the nearest galaxy?

You may have read or heard that Andromeda is the galaxy closest to us, but that’s not entirely correct.

Located about 2.5 million light-years from Earth, Andromeda is the closest massive galaxy to us, but not the closest (just) galaxy.

Orbiting our galaxy are dozens of small satellite galaxies and of all of them, the Can Mayor Dwarf is the closest, located only about 0.025 million light years.

What is the age of the universe?

From the Cosmic Microwave Background, scientists have been able to estimate the age of the Universe at 13,787 million years, with a maximum error of 200 million years.

What is the size of the universe?

Using data from the same Cosmic Microwave Background and observing the most distant galaxies, scientists have calculated that the size of the observable universe is approximately 46.5 billion light years.

But watch out! That’s just the Observable Universe, that is, the maximum distance we can see.

Beyond that distance there is still the Universe, the problem is that the light from those regions has not yet had time to reach us and therefore we do not see them.

Calculating the total size of the universe is impossible. First because as we have said, if the light from those areas does not reach us we cannot see them and second, the Universe continues to expand at an accelerated rate.

What was the big bang?

The Big Bang is the very beginning of the cosmos. A process by which we go from not existing to existing.

All the energy in the universe was compressed into a point called the singularity. At one point, that singularity expanded just like a balloon expands when you breathe air into it.

Our Universe and everything in it, including time and space, was born.

How or why this happened remains a real mystery that we try to solve in places like the LHC.

What color is the sun?

The Sun is a yellow dwarf star of type G-II. This means that its light is within the yellow spectrum.

Although because of the intensity of its light, if we look at the Sun from pictures of the International Space Station (ISS), it really looks white.

What is a comet?

A comet is a body composed wholly or partly of ice, formed in the confines of the Solar System.

As a comet approaches the Sun, its material begins to rise, creating the characteristic coma and tail that we are accustomed to seeing.

How does a star work?

Stars work by fusing two hydrogen atoms into one helium atom, specifically thousands of tons of hydrogen every second.

The energy released during these nuclear fusions is what reaches us in the form of light, heat and radiation in general.

In larger stars, the process doesn’t stop there; it continues to fuse helium into heavier and heavier elements until it reaches iron.

If you are interested in this topic, you will probably like this article on the future death of the Sun.

What is a black hole?

A black hole is a region of space with a gravitational pull so extreme that even light cannot escape it.

These colossal objects are born from supernovae of giant stars or from the collision of multiple stars (supermassive black holes).

Since nothing can escape from the event horizon of a black hole, knowing what is there and how the laws of physics work inside it is a mystery that we will probably never be able to solve.

How did the Solar System form?

After the supernova death of a large star, a nebula rich in ionized molecular hydrogen formed.

By the force of gravity, these atoms began to group together, increasing the pressure and temperature and forming a protostar that would later become the Sun.

The gravity of this new object created a disk around it that caused larger and larger particles to collide with each other, giving rise to the planets and moons we know today.

What is the temperature of the universe?

This is a difficult question, mainly because there is no global temperature for the whole cosmos.

We ourselves on Earth notice this, it is not the same temperature in a place during the day as it is at night, neither in summer nor in winter.

The Cosmic Background Explorer (COBE) satellite made a more specific measurement of the temperature of the universe, the cosmic background radiation (CBR). According to the spectrometers this would be 2,726 degrees Kelvin (2,452.86 degrees °C), with a margin of error of one hundredth of a degree.