Second, matter in the early universe was dense and opaque, so it is inaccessible to observations. First, there are hundreds of billions of galaxies and countless stars, but only one universe, so we don’t have any way to compare the possibilities if things are slightly different. Theory is necessary for cosmology - the study of the whole universe - for two major reasons. Astrophysicists use advanced mathematics and computer simulations to model star clusters, multi-planet or -moon systems, and many more. Theoretical models help constrain the possibilities, based on the environments for exoplanets we observe.Ĭalculating gravitational interactions between three or more objects is still a challenging problem. We only know of one planet where life exists, but with thousands of known exoplanets and billions more likely in the Milky Way alone, researchers want to know how possible life is elsewhere. Today, researchers model star and planet formation using computers, to understand the details of the magnetic fields of the newborn stars, the way planets migrate within the protoplanetary environment, and other details. Star- and planet-formation models indicate that stars and planets are born from dense, cold clouds of gas and dust, which we describe by modeling the way matter collapses under its own gravity when compressed. Theoretical astrophysics covers as wide a range of topics as observational astronomy. In other instances, astronomers observe phenomena for which theorists don’t have an explanation, such as the accelerating expansion of the universe. Sometimes theory predicts new phenomena that are later observed, such as gravitational waves, which were first described in 1916, but only detected a century later. In that way, observations are the test of theory, and theory is the explanation for observations. Theory produces a mathematical description or model of certain systems, which generalizes data taken from particular observations to explain them and others. Science needs both theory and data collected through observation or experiment. The most powerful theories both explain what we observe in a coherent way and predict new phenomena, providing us with deep insights into how the universe works. Theory is the way scientists connect facts into a coherent system of thinking, which they can use to understand the natural world. Theorists Propose a New Method to Probe the Beginning of the Universe Early-universe researchers examine the different possible ways inflation could have worked, including potential observable effects. Inflation explains many aspects of the universe we see today, but we have no direct evidence for it. Calculations show that these exoplanets may be uninhabitable based on magnetic activity and solar wind.ĭetermining the nature of inflation, the extraordinarily rapid expansion of the cosmos that many cosmologists think occurred when the universe was just a split-second old. That means potentially habitable worlds in these systems are very close to the star, possibly too close. Astronomers have discovered a number of planets orbiting red dwarf stars, which are much lower temperature than the Sun. New Evidence That All Stars Are Born in PairsĬalculating the potential conditions on exoplanets orbiting a variety of stars. Those binaries may be disrupted later, as happened with our Sun, but the theory suggests there’s a twin Sun somewhere out there. Using the data from star-forming regions and theoretical calculations of gas and dust under the action of gravity, astrophysicists have concluded stars tend to be born in pairs.
Center for Astrophysics | Harvard & Smithsonian theoretical astrophysicists study a wide range of phenomena:īuilding models of star-formation based on observation and theory.
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