Atomic and molecular astrophysics facts for kids

This amazing picture from the Hubble Space Telescope shows a molecular cloud. These are giant clouds of gas and dust where new stars are born. This cloud is part of the famous Carina Nebula.

Atomic and molecular astrophysics is the exciting field where scientists study the atoms and molecules found all across space. Everything we know about distant stars and galaxies comes from the light they send us. By studying this light, astronomers can figure out what things in the universe are made of.

This field helps us understand how stars and planets are born from giant clouds of gas and dust. It's like being a space detective, using clues from light to solve the mysteries of the cosmos.

What Are Atoms and Molecules in Space?

To understand the universe, scientists first look at its smallest parts: atoms and molecules.

The Building Blocks: Atoms

Atomic astrophysics focuses on studying the atoms in space. Atoms are the tiny particles that make up everything, from the air you breathe to the most distant stars.

When atoms in a star get very hot, they release energy in the form of light. Each type of atom, like hydrogen or helium, gives off its own unique pattern of light. This pattern is like a "fingerprint." By looking at these light fingerprints, astronomers can tell exactly what atoms a star is made of, even from millions of light-years away.

Putting Them Together: Molecules

Molecular astrophysics is the study of molecules in space. When two or more atoms join together, they form a molecule. For example, a water molecule (H₂O) is made of two hydrogen atoms and one oxygen atom.

Molecules are usually found in cool, dark places in space. The most massive objects in our Milky Way galaxy are giant clouds of molecules and dust. These are called molecular clouds. These clouds are super important because they are "star nurseries" where new stars and planets are formed. A key scientist who helped develop this field was Alexander Dalgarno, starting in 1967.

How Do We Find Molecules in Space?

Finding molecules in the cold, dark parts of space requires special tools and methods.

Listening for Molecular Signals

Most molecules in space are too cold to glow with light we can see. Instead, they send out energy at longer wavelengths, like radio waves. Scientists use huge radio telescopes on Earth to "listen" for these faint signals.

One of the most important molecules they search for is carbon monoxide (CO). It is made of one carbon atom and one oxygen atom. It is very common and helps scientists map the location and size of the giant molecular clouds where stars are born. The signal from CO has a wavelength of 2.6 millimeters, which is a type of radio wave.

Why Build Telescopes on Mountains?

The signals from space molecules can be blocked by water in Earth's atmosphere. To get a clear signal, scientists build telescopes in very high and dry places. This is why many of the world's best observatories are on top of tall mountains in deserts. The radio telescopes also need to have very smooth, precise surfaces to capture high-quality images of these molecular clouds.

Are There Building Blocks of Life in Space?

One of the most exciting questions in astrophysics is whether the ingredients for life exist elsewhere in the universe.

On February 21, 2014, NASA announced that it had created a new database to track special molecules in space called polycyclic aromatic hydrocarbons (PAHs). These are large, complex molecules made of carbon and hydrogen atoms.

Scientists think that more than 20% of all the carbon in the universe might be in the form of PAHs. These molecules are found almost everywhere, from clouds where new stars are forming to the areas around exoplanets. Because they are so common, some scientists believe PAHs could be the starting materials for the formation of life.

See also