Most magnetic fields are man-made. They are found in solenoids, bar magnets and some motors and transformers. Magnetic fields are used in creative ways to create sound, microscopic images and record resonance images through MRI technology. In some cases, however, the fields interfere with sensitive electronic equipment and shielding is necessary. See similar questions...

The inner core and outer core of the planet are composed primarily of iron and nickel. The outer core is liquid and the inner core is solid. It is thought that the convective motion of the liquid outer core is responsible for generating the main field. Recent studies indicate that the inner core of the Earth may rotate a bit faster than the outer core and it is possible that this rotation may be associated with field reversals. See similar questions...

All the cells of the body have a weak, natural electric current flowing through them. The currents are caused by electrically charged particles in the cells called ions. Ions affect the metabolism, or the work of the cell. PMFT is a method of applying a magnetic field to the cell which sends a weak electrical signal, influencing the interaction of the ions, and the flow of nutrients in the cell. Enhanced circulation and nutrient exchange can speed the healing process and reduce down time. See similar questions...

Because the Earth's magnetic field is constantly changing, it is impossible to accurately predict what the field will be at any point in the very distant future. By constantly measuring the magnetic field, we can observe how the field is changing over a period of years. Using this information, it is possible to create a mathematical representation of the Earth's main magnetic field and how it is changing. See similar questions...

The Earth's magnetic field is slowly changing and appears to have been changing throughout its existence. When the tectonic plates form along the oceanic ridges, the magnetic field that exists is imprinted on the rock as they cool below about 700 Centigrade. The slowly moving plates act as a kind of tape recorder leaving information about the strength and direction of past magnetic fields. See similar questions...

Magnetic fields are historically described in terms of their effect on electric charges. A moving electric charge, such as an electron, will accelerate in the presence of a magnetic field, causing it to change velocity and its direction of travel. This is, for example, the principle used in televisions, computer monitors, and other devices with CRTs (cathode-ray tubes). In a CRT, electrons are emitted from a hot filament. See similar questions...

Fields fill the space between matter and they determine how it is that bits of matter can exert forces on other bits of matter at a distance. There are several different fields in nature, and their reality is demonstrated by our observation of the forces with which they are associated. So, for example, gravitational fields determine how it is that objects with mass are attracted together by a gravitational force. See similar questions...

NightStar can affect a pacemaker's normal mode of operation. If the heart rate of a person with a pacemaker drops below a preset value (typically 85 beats per minute), an internal sensor monitoring the person's heart rate activates the pacemaker. A pacemaker will not send electrical signals to a person's heart unless their heart rate drops below the preset value. See similar questions...

The Earth's magnetic field is actually a composite of several magnetic fields generated by a variety of sources. These fields are superimposed on each other and through inductive processes interact with each other. The most important of these geomagnetic sources are: a. the Earth's conducting, fluid outer core (~90%); b. magnetized rocks in Earth's crust c. fields generated outside Earth by electric currents flowing in the ionosphere and magnetosphere d. See similar questions...

The accuracy of a model in calculating the magnetic field influencing a compass or other magnetic sensor is affected by many things, including where you are using the compass. In general, the present day field models such as the IGRF and World Magnetic Model (WMM) are accurate to within 30 minutes of arc for D and I and about 200 nanoTesla for the intensity elements. It is important to understand that local anomalies exceeding 10 degrees, although rare, do exist. See similar questions...

While we now appear to be in a period of declining magnetic field strength, we cannot state for certain if or when a magnetic reversal will occur. Based on measurements of the Earth's magnetic field taken since about 1850 some paleomagnetists estimate that the dipole moment will decay in about 1,300 years. See similar questions...

Yes, the magnetic field is different in different places. In fact, the magnetic field changes with both location and time and changes the way it is changing. It is so irregular that it must be measured in many places to get a satisfactory picture of its distribution. This is done using satellites, at the approximately 200 operating magnetic observatories worldwide, and at several more temporary sites. However, there are some regular features of the magnetic field. See similar questions...

Elementary physics states that the magnetic field of a magnetic dipole is approximately proportional to the inverse square of the distance from the dipole. Therefore, if you double the distance from the magnet, the magnetic field strength will be reduced (roughly) by a factor of 4. See similar questions...

No, unlike magnetic field therapy, with PST the magnetic field only serves as the "carrier" for the electrically pulsed signals. The magnetic field allows these signals to penetrate the injury unchanged. Without the magnetic field, the pulsating signals would be distorted by varying density of the surrounding tissue. See similar questions...

It is an alternative treatment method which can even be used to treat health concerns with sometimes unbelievable therapeutic success - this has been proved in international medical and scientific studies (read our collected "research" section). Well-intentioned explanations refer to it as a biological treatment method. However, that is a generalization. Magnetic Field Therapy is actually one of the oldest treatment methods around, and it is based on physical principles. See similar questions...

Magnetic field complexity can be realised in a number of forms. For instance, complexity could be a field that is changing in strength (amplitude) either regularly (indicating an amplitude modulated field) or irregularly. The degree and magnitude of the change could also be altering adding another component to the complexity. Another factors might be mixed field frequencies. There may be many different frequency components contained within the measured fields and these may come and go. See similar questions...

lt;fields> <field type="Solenoid" name="GlobalSolenoid" inner_field="5.0" outer_field="-0.6" zmax="1000" outer_radius="144*cm+(2+1)*34*cm"/> </fields> See similar questions...

Yes. We know this from an examination of the geological record. When lavas are deposited on the Earth’s surface, and subsequently freeze, and when sediments are deposited on ocean and lake bottoms, and subsequently solidify, they often preserve a signature of the ambient magnetic field at the time of deposition. This type of magnetization is known as 'paleomagnetism'. See similar questions...

Pulsed magnetic field therapy applies a magnetic field to the cells, which sends a signal that influences the interaction of ions which have a natural electric current flowing through them. These signals initiate biologic reactions which accelerate healing. PMFT is applied with the use of a jacket, which allows the dog to sit, stand, walk, or lie down while receiving therapy. See similar questions...