Space physics

Scientists study things in space. They look at the Sun and the air high up. They also study the lights in the sky. These lights are called aurorae.

Space can change our weather. The Sun sends out wind to space. This wind can move through our air.

We use rockets to learn more. Some rockets go very high. They find belts of energy around Earth.

We also use tools on satellites. These tools help us talk to each other. They help us send signals from far away. Space is a very busy place!

Space physics is the study of plasmas in space. A plasma is a special kind of gas. These plasmas exist in our air and the Solar System. Scientists study the Sun and solar wind. Solar wind is a stream of particles from the Sun. They also study aurorae. These are the bright lights in the sky.

People have watched these lights for a long time. Old Greek writers called them burning clouds. In the 1500s, William Gilbert said Earth is a big magnet. This helps explain why a compass points north. Later, scientists saw that the Sun affects Earth. Sunspots might send fast particles toward our poles.

We use many tools to learn more. Some tools are on rockets. Other tools are on spacecraft. The Van Allen belts are rings of radiation around Earth. These were found by early satellites. New tools like the Parker Solar Probe study the Sun. Space physics helps us use radio signals. It also helps us fly spacecraft.

Space physics is the study of plasmas in our space. A plasma is a special kind of gas found in the Solar System. Scientists look at the Sun and the solar wind. This solar wind is a stream of particles from the Sun. They also study the aurorae, which are bright lights in the sky. This science helps us understand how things work in the upper atmosphere. It even helps us send radio signals and fly spacecraft.

Learning about space happens in many ways. Some scientists use sounding rockets to take direct measurements. Other people use spacecraft to fly through space. They can also use radar to look at plasmas from far away. This is called remote sensing. Some researchers use math and models to study these things. They might use fluid theory or kinetic theory to understand the movements.

People have watched the lights in the sky for a long time. Chinese sources describe aurorae from 2000 B.C.E. A Greek writer named Xenophanes wrote about them in the sixth century B.C.E. He called them moving clouds of burning light. In the eleventh century, Chinese sources invented the compass. This showed that Earth has a magnetic field. Later, William Gilbert described this field in the 1500s.

Many scientists helped us learn the truth. In 1747, Anders Celsius and Olof Peter Hiorter saw a link between aurorae and magnetic changes. Elias Loomis found that aurorae happen near the magnetic poles in 1860. In the 1950s, a team led by Van Allen launched rockets to 110 km. The Sputnik 2 and Explorer 1 satellites found the radiation belts. These are now called the Van Allen belts.

Space physics connects to many things we use today. It helps us manage weather satellites and communication. We use this knowledge to help meteorology, which is the study of weather. Spacecraft like WIND and ACE study the solar wind. The Parker Solar Probe also studies the Sun. Even the IBEX spacecraft studies the space between stars.

Space physics is the study of naturally occurring plasmas. A plasma is a specific state of matter found in the upper atmosphere and the Solar System. This field includes many complex topics like aeronomy and aurorae. It also investigates planetary ionospheres and magnetospheres. Scientists study radiation belts and space weather within this discipline. They also look at the solar wind and the Sun. More recently, the field has expanded to include the interstellar medium. This science is vital for our modern world. It helps with radio transmission and spacecraft operations. It is also useful for meteorology and managing weather satellites.

Researchers use several methods to understand these cosmic processes. Some use in situ measurements to take direct readings. They do this using sounding rockets and various spacecraft. Other scientists use remote sensing to study plasmas from a distance. They might use radar methods like Incoherent scatter. They also use GPS scintillation to gather data. Many experts also perform theoretical studies. They use models like magnetohydrodynamics, which is a type of fluid theory. They may also use kinetic theory to understand particle movements. These different approaches help map the invisible forces of space.

Space physics is closely linked to several other scientific fields. Plasma physics studies the most fundamental physics of these materials. It also looks at laboratory plasmas and fusion plasmas. Atmospheric physics and atmospheric chemistry investigate the upper layers of Earth's atmosphere. There is also astrophysical plasmas, which involves natural plasmas found beyond our Solar System. These connections allow scientists to see how small particles affect large systems. Understanding these links helps us predict how the Sun affects Earth.

Humans have observed space phenomena for thousands of years. Chinese sources describe aurora-like features from 2000 B.C.E. In the sixth century B.C.E., the Greek writer Xenophanes observed them too. He described them as moving accumulations of burning clouds. Around the eleventh century, Chinese sources invented the compass. This was an early sign of a global geomagnetic field. In the 16th century, William Gilbert wrote De Magnete. He explained that the Earth acts like a great magnet. This discovery helped explain why compass needles point north.

Many researchers helped build our modern understanding of magnetism. George Graham studied magnetic declination near London. He discovered irregular fluctuations called magnetic storms. Alexander Von Humboldt later gave these storms their name. Gauss and William Weber made very precise magnetic measurements. Their work suggested that external forces influence the Earth. They noticed these forces came from the Sun and sunspots. In 1747, Anders Celsius and Olof Peter Hiorter linked aurorae to magnetic disturbances. In 1860, Elias Loomis found aurorae occur in an oval around the magnetic pole.

New theories emerged as scientists studied particle movement. In the late 1870s, Henri Becquerel suggested sunspots release fast protons. He believed the Earth's magnetic field guides these to the poles. In the early 1900s, Kristian Birkeland built a terrella. This was a laboratory device that simulated Earth's magnetic field in a vacuum. He used a cathode ray tube to simulate the solar wind. This helped create a theory about how the solar wind interacts with Earth. These early experiments laid the groundwork for modern space science.

Modern space physics began with direct measurements in the 1950s. A team led by Van Allen launched rockets to 110 km. The Sputnik 2 and Explorer 1 satellites detected radiation belts. These are now known as the Van Allen belts. Explorer 10 later studied the boundary of Earth's magnetic field. Since then, many spacecraft have explored deeper into space. The WIND spacecraft and the Advanced Composition Explorer (ACE) study the solar wind. The Ulysses and IBEX missions look at different parts of space. The Parker Solar Probe and SOHO also study the Sun directly.