Cosmology has reached an era where precise calculations can be made of the contr
ID: 2304147 • Letter: C
Question
Cosmology has reached an era where precise calculations can be made of the contri butions of ordinary matter and radiation, dark matter, and dark energy, to the energy density of the Universe. Our Universe at this time is thought to be dominated by dark matter and dark energy, which together make up about 95% of the energy density. Or- di In the following, ?? is the current nary matter and radiation make up the last 5% value of the density of dark energy, and S2m refers to the energy density of everything .all al mar, dark matter, aul ralati. a) What is the effect of dark energy on the expansion of the Universe? Explain how type Ia supernova observations are used to constrain the relative contributions of dark energy and all other matter to the energy density of the Une 4Explanation / Answer
Dark matter and dark energy describe proposed solutions to gravitational phenomena.
Dark energy is responsible for cosmic speeding. It is invocked to explain weaker than expected and in fact negative gravitational attraction.
This energy is a property of space itself and would not be diluted as space expands. It increases as the more space comes in to the existence , as a result this form of energy would cause the universe to expand faster and faster.
Type Ia Supernova are thought to occur when white dwarf star strips mass off an orbiting companion star until it becomes massive enough to explode.
Type Ia SNe all have a similar peak luminicity and the time it takes to decrease in luminicity. Less luminous SNe decay more rapidly while more luminous SNe decay slowly.
A one - parameter fit reduces scatter in peak luminicity significantly.
Taken together, these features make Type Ia SNe valuable cosmological probe: they are bright enough to be detected at great distances and act as standardizable candles for distance determination.
Although there will be some uncertainties due to main sources. Observations of Type Ia SNe at different redshifts can thus be used to estimate the distance-redshift relation , and in turn the dark energy equation of state.