Scientists study subatomic particles by examining the telltale trails, such as those shown here, their passage leaves behind in a bubble chamber. This image shows the first detection of a neutrino. Click on image for full size (144K GIF) Image courtesy Argonne National Laboratory.

Atoms and the minute particles from which they are made strongly influence the nature of many phenomena that play out their roles on astronomical scales. The fields of atomic physics and particle physics provide many valuable insights into the life cycles of stars, the forms of spaceborne radiation, the way we can use spectra to study distant objects, and many other topics in space science.

The discipline of atomic physics concerns itself with atoms, the particles from which atoms are made, and the various energy states that atoms can take on. The tiny, dense nucleus of an atom is made up of protons and neutrons. Clouds of electrons, less than a thousandth the size of the nucleons, buzz around the nucleus in a complex array of energy states. The behavior of objects at these miniscule size scales defies our experience, so various models of the atom have been devised over time to help us comprehend these fundamental constituents of the elements that make up matter.

Particle physics delves into scales even smaller than the atom as it sheds light on the worlds of subatomic physics. When atoms are torn apart, usually in the presence of large amounts of energy, subatomic particles come out to play. Some are familiar, such as protons, neutrons, and electrons; others are more exotic, bearing strange names like muon, neutrino, baryon, meson, and the elusive quark. Plasmas, such as the "soup" of electrons and protons that makes up the solar wind, and many of the most dangerous forms of radiation, such as cosmic rays, are collections of subatomic particles that particle physicists study.

The "laws" of physics at atomic and subatomic scales are so different from those we observe in our "normal" daily experiences that physicists had to invent a whole new field to describe them. The discipline of quantum mechanics, born in the early part of the 20th century, predicts the strange behaviors found in the worlds of the very small. In the realms of quantum physics, the distinctions between particles and waves disappear, we lose our ability to define the locations of objects in favor of probabilistic descriptions of where particles are likely to be, and the mere act of observing a phenomenon can fundamentally alter its behavior. Although the size scales are small, the impacts of events in the worlds of atoms and subatomic particles and the domain of quantum mechanics are huge!

Scientists study subatomic particles by examining the telltale trails, such as those shown here, their passage leaves behind in a bubble chanmber. This image shows the first detection of a neutrino. Click on image for full size (144K GIF) Image courtesy Argonne National Laboratory.

Atoms and the minute particles from which they are made strongly influence the nature of many phenomena that play out their roles on astronomical scales. The fields of atomic physics and particle physics provide many valuable insights into the life cycles of stars, the forms of spaceborne radiation, the way we can use spectra to study distant objects, and many other topics in space science.

The discipline of atomic physics concerns itself with atoms, the particles from which atoms are made, and the various energy states that atoms can take on. The tiny, dense nucleus of an atom is made up of protons and neutrons. Clouds of electrons, less than a thousandth the size of the nucleons, buzz around the nucleus in a complex array of energy states. The behavior of objects at these miniscule size scales defies our experience, so various models of the atom have been devised over time to help us comprehend these fundamental constituents of the elements that make up matter.

Particle physics delves into scales even smaller than the atom as it sheds light on the worlds of subatomic physics. When atoms are torn apart, usually in the presence of large amounts of energy, subatomic particles come out to play. Some are familiar, such as protons, neutrons, and electrons; others are more exotic, bearing strange names like muon, neutrino, baryon, meson, and the elusive quark. Plasmas, such as the "soup" of electrons and protons that makes up the solar wind, and many of the most dangerous forms of radiation, such as cosmic rays, are collections of subatomic particles that particle physicists study.

The "laws" of physics at atomic and subatomic scales are so different from those we observe in our "normal" daily experiences that physicists had to invent a whole new field to describe them. The discipline of quantum mechanics, born in the early part of the 20th century, predicts the strange behaviors found in the worlds of the very small. In the realms of quantum physics, the distinctions between particles and waves disappear, we lose our ability to define the locations of objects in favor of probabilistic descriptions of where particles are likely to be, and the mere act of observing a phenomenon can fundamentally alter its behavior. Although the size scales are small, the impacts of events in the worlds of atoms and subatomic particles and the domain of quantum mechanics are huge!

Scientists study subatomic particles by examining the telltale trails, such as those shown here, their passage leaves behind in a bubble chanmber. This image shows the first detection of a neutrino. Click on image for full size (144K GIF) Image courtesy Argonne National Laboratory.

Did you know that a lot of what happens in space physics has to do with the interaction of really tiny particles? These particles like protons and electrons are so tiny that you can't even see them with your naked eye. That means you'd need special instruments to detect that they are even there.

The study of these tiny particles is called atomic physics and particle physics. Other particles have funny names like muon, neutrino, meson, and quark.

The "laws" of physics at atomic scales are so different from those we see in our "normal" experiences that physicists had to invent a whole new field in the early part of the 20th century to describe them. This field is called quantum mechanics.