Question: What model would an astrophysicist use to study come phenomena and unseen effects?
About the article "Astrophysics", section "Theoretical astrophysics".

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Theoretical astrophysicists use a wide variety of tools which include analytical models (for example, polytropes to approximate the behaviors of a star) and computational numerical simulations.
Each has some advantages.
Analytical models of a process are generally better for giving insight into the heart of what is going on.
Numerical models can reveal the existence of phenomena and effects that would otherwise not be seen.
Theorists in astrophysics endeavor to create theoretical models and figure out the observational consequences of those models.
This helps allow observers to look for data that can refute a model or help in choosing between several alternate or conflicting models.
Theorists also try to generate or modify models to take into account new data.
In the case of an inconsistency, the general tendency is to try to make minimal modifications to the model to fit the data.
In some cases, a large amount of inconsistent data over time may lead to total abandonment of a model.
Topics studied by theoretical astrophysicists include: stellar dynamics and evolution; galaxy formation and evolution; magnetohydrodynamics; large-scale structure of matter in the universe; origin of cosmic rays; general relativity and physical cosmology, including string cosmology and astroparticle physics.
Astrophysical relativity serves as a tool to gauge the properties of large scale structures for which gravitation plays a significant role in physical phenomena investigated and as the basis for black hole ("astro")physics and the study of gravitational waves.
Some widely accepted and studied theories and models in astrophysics, now included in the Lambda-CDM model are the Big Bang, Cosmic inflation, dark matter, dark energy and fundamental theories of physics.
Wormholes are examples of hypotheses which are yet to be proven (or disproven).
Theoretical astronomers use a wide variety of tools which include analytical models (for example, polytropes to approximate the behaviors of a star) and computational numerical simulations.
Each has some advantages.
Analytical models of a process are generally better for giving insight into the heart of what is going on.
Numerical models can reveal the existence of phenomena and effects that would otherwise not be seen.
Astronomy theorists endeavor to create theoretical models and figure out the observational consequences of those models.
This helps observers look for data that can refute a model or help in choosing between several alternate or conflicting models.
Theorists also try to generate or modify models to take into account new data.
Consistent with the general scientific approach, in the case of an inconsistency, the general tendency is to try to make minimal modifications to the model to fit the data.
In some cases, a large amount of inconsistent data over time may lead to total abandonment of a model. 
David Norman Schramm (October 25, 1945 – December 19, 1997) was an American astrophysicist and educator, and one of the world's foremost experts on the Big Bang theory.
Schramm was a pioneer in the study of Big Bang nucleosynthesis and its use asa probe of dark matter (both baryonic and non-baryonic) and of neutrinos.
He also made important contributions to the study of cosmic rays, supernova explosions, and heavy-element nucleosynthesis. 
Theoretical astronomers use several tools including analytical models (for example, polytropes to approximate the behaviors of a star) and computational numerical simulations.
Each has some advantages.
Analytical models of a process are generally better for giving insight into the heart of what is going on.
Numerical models reveal the existence of phenomena and effects otherwise unobserved.
Theorists in astronomy endeavor to create theoretical models and from the results predict observational consequences of those models.
The observation of a phenomena predicted by a model allows astronomers to select between several alternate or conflicting models.
Theorists also try to generate or modify models to take into account new data.
In the case of an inconsistency, the general tendency is to try to make minimal modifications to the model so that it produces results that fit the data.
In some cases, a large amount of inconsistent data over time may lead to total abandonment of a model.
Topics studied by theoretical astronomers include: stellar dynamics and evolution; galaxy formation; large-scale structure of matter in the Universe; origin of cosmic rays; general relativity and physical cosmology, including string cosmology and astroparticle physics.
Astrophysical relativity serves as a tool to gauge the properties of large scale structures for which gravitation plays a significant role in physical phenomena investigated and as the basis for black hole ("astro")physics and the study of gravitational waves.
Some widely accepted and studied theories and models in astronomy, now included in the Lambda-CDM model are the Big Bang, Cosmic inflation, dark matter, and fundamental theories of physics.
A few examples of this process:Dark matter and dark energy are the current leading topics in astronomy, as their discovery and controversy originated during the study of the galaxies. 
Geography (from Greek , "geographia", lit.
"earth description") is a field of science dedicated to the study of the lands, the features, the inhabitants, and the phenomena of the Earth.
A literal translation would be "to describe or write about the Earth".
The first person to use the word "geography" was Eratosthenes (276–194 BC).
Four historical traditions in geographical research are spatial analysis of the natural and the human phenomena (geography as the study of distribution), area studies (places and regions), study of the man-land relationship, and research in the Earth sciences.
Nonetheless, modern geography is an all-encompassing discipline that foremost seeks to understand the Earth and all of its human and natural complexities - not merely where objects are, but how they have changed and come to be.
Geography has been called "the world discipline" and "the bridge between the human and the physical science".
Geography is divided into two main branches: human geography and physical geography.