## Gravity Anomaly: All You Must Know About the Anomalies

There are basically two ways to find out the gravity field of Earth - through the maps of the Earth’s geoid and the anomaly. The main purpose of the anomaly maps is to discover the difference between the uniform Earth surface and the actual gravity field. In simple words, anomaly maps are used to tell the difference in the gravitational force on the planet’s surface. The question is what causes the anomaly or why does this variation on the surface of the earth exist? One of the common reasons is the differences in the volume of the mass present in these areas. Let’s understand this with an example. The mountain ranges on Earth are known for increasing the gravitational force and making it more than it is on the featureless planet. This is commonly called the positive gravity anomaly, in which the gravitational force on the planet increases due to the high concentration of mass. On the other hand, the ocean trenches have a negative impact on the gravity anomaly. What is Geoid? What Role Does it Play in Determining the Gravity Anomaly? Geoid refers to the theoretical earth surface that shows us the seal level when there are no winds, tides, or currents. In other words, the geoid is the reference earth’s surface. Architects and surveyors use this reference earth surface when it comes to laying out the highway. It has never been easy for scientists to prepare an accurate model of Geoid. Until now, we did not have one source that could be used for the measurement of the gravitational force. Scientists had to use the data from multiple satellites, including the measurements taken from the ships in the sea and over the land. These things were combined in order to come up with the gravitational field. There is no denying that these models, even though they were pretty complex, did an amazing job at showing the large-scale characteristics of the gravitational force. However, they did not work out for producing the finer-scale features precisely. Is the Measurement of Gravity Anomaly Important? Researchers need a more detailed geoid map to get a clear picture of the earth’s surface and the gravity field. Thanks to the GIS (geographic information system), it has now become possible for scientists to discover more about the earth’s gravitational force and get a clear picture of the surface of the earth along with other features. First things first, the technology helps in the calculation of the changing mass of the polar ice caps, in addition, it allows you to get a better understanding of the atmosphere-ocean mass exchange. It is extremely important for scientists to calculate the gravity anomaly since it exposes the rock density variations and other important features that give you more details about the earth’s surface and the variations in the gravitational force. Note that the gravity anomaly provides only a little information about the earth’s surface if it’s collected from a single location, which is why the data is often combined with the values taken from the surrounding areas.