Freedman carnegie observatories, 8 santa barbara st. The hubble constant and the expansion age of the universe wendy l. In an appendix, i claim that hubbles law might yet to be investigated for its ultimate cause, and suggest the hubble effect as the searched candidate. Dec 21, 2012 presumably, the universe itself is at least as old as the oldest globular clusters that reside in it. Blue is colder and red is warmer, by less than 1 of a degree. May 17, 2017 how do we know the age of the universe. Cosmologists use this measurement to extrapolate back to the big bang. Hubble measures the expanding universe science mission. Why cosmologys expanding universe controversy is an even. This provocative question will be addressed only by describing the models we have of the expanding universe and the big bang process. After eight years of cepheid observations this work was concluded by finding that the expansion increases with 70 kmsecond for every 3.
Traditionally, the present value of the hubble parameter is written as. Much evidence suggests that the universe is very nearly flat, i. The observed cmb angular power spectrum provides powerful evidence in support of. The colors represent slight differences from the average temperature of 2. Indeed antimatter is only detected in accelerators or in cosmic rays. Age of the universe three competing terms drive the expansion. Time scale of primordial universe is extremely different milne universe spends much more time at high temperature than conventional universe bbn duration standard bbn. One of the biggest mysteries in the universe is the fact there theres matter, and not antimatter. The present universe is a result of evolution expands initial state was very different big bang age. Measuring the age and size of the universe esahubble esa. The age of the universe dilemma is probably the link between these two issues. Feb 20, 2018 what kinds of tools do astronomers use to calculate the age of the universe, and how can they determine the speed of its expansion. Volkas submitted in total ful lment of the requirements of the degree of doctor of philosophy in the school of physics the university of melbourne july 2015 produced on archival quality paper. One way to check the hubble constant is to compare its prediction for the age of the universe with the age of the oldest objects we can see.
Age of the milne universe is almost exactly the same as the age of. The hubble space telescope key project team today announced that it has completed efforts to measure precise distances to far flung galaxies, an essential ingredient needed to determine the age, size and fate of the universe. The uncertainty has been narrowed down to 20 million years, based on a number of studies which all gave extremely similar figures for the age. Nov 17, 2014 one of the biggest mysteries in the universe is the fact there theres matter, and not antimatter. Value of hubbles time age of universe scientists references.
This extrapolation depends upon the current density of the universe and on the composition of the universe. Jan 24, 2014 by characterizing the detailed structure of the cosmic microwave background fluctuations, wmap has accurately determined the basic cosmological parameters, including the hubble constant. The expansion rate of the universe is known as the hubble constant. In fact, the temperature of the cmb gives very little informationjust one number. These particles include almost equal amounts of matter and antimatter.
How is hubble constant calculated from cosmic microwave. I came accross a problem under cosmology in the txt book they hav given a equation for the age of the universe using the hubble constant. Pdf antimatter and antistars in the universe and in the. Cosmic microwave background cmb radiation from the hot matter of the universe soon after the big bang. Here i show how some simple data can be used to plot a graph of hubble s law, from which we can calculate the age of the universe.
The big bang the cosmic microwave background cmb a brief history of time apr 25, 2005 astronomy 122 spring 2006 the hubble law and the age of the universe we can use the hubble law to estimate the age of the universe. Big bang theory 2 age of the universe time since any galaxy left origin is dv distancevelocity velocity is given by hubbles law, vhd age dv d hd 1 h. The faster the universe is expanding, the faster the galaxies will appear to be moving away from each other. For many years, until about 10 years ago, however, there was a controversy over the age of the universe derived from hubble s constant. The hubble constant h 0 is a measure of the current expansion rate of the universe. One of hubble s initial core purposes was to determine the rate of expansion of the universe, known to astronomers as the hubble constant. The present rate of the universe s expansion can be predicted from the cosmological model using measurements of the early universe, as encoded in the cosmic microwave background cmb. Hubbles law and the age of the universe physics forums. This is a great instructional video on how to calculate the age of universe from hubbles constant. The cmb is faint cosmic background radiation filling all space. Hubble helps with new measurement for universes age. As the expansion rate has varied over the lifetime of our universe, we denote the presentday value of the hubble constant as h o. The cmb is a remnant of an earlier cosmological epoch.
Hubbles law states that the speed of a distant object is proportional to its distance this implies an expanding universe. Hubble discovers the expansion of the universe 1948early 50s george gamow, ralph alpher, and. This means that the closed universe has been expanding for a. The cosmic microwave background cmb is thought to be leftover radiation from the big bang, or the time when the universe began. The radiation is isotropic to roughly one part in 100,000. Hubble thanks to the hubble space telescope, astronomers are using ancient stars in the milky way to come up with an independent estimate about the. Whole universe is in state of expansion current expansion implies whole universe much more compact in past hubble law gives idea of time since universe began.
Big bang theory 2 age of the universe time since any galaxy left origin is dv distancevelocity velocity. Hubble thanks to the hubble space telescope, astronomers are using ancient stars in the milky way to come up with an independent estimate about the age of the universe. The explanation gives the computational details 1hubble constant is an estimate for the age of our universe. Early universe cosmology and the matterantimatter asymmetry author.
The hubble constant and the expansion age of the universe. The current best direct measurement of the hubble constant is 73. Traditionally, the present value of the hubble parameter is written as h 0 h 100 km s mpc. Hubbles constant is equal to velocity over distance.
The hubble time is the age it would have had if the expansion had been linear, and it is different from the real age of the universe because the expansion is not linear. Noting the similarities with our universe age, sn1a luminosity distance, nucleosynthesis, cmb angular scale, we focus our attention on. Presumably, the universe itself is at least as old as the oldest globular clusters that reside in it. Various cosmological parameters are inferred from the cmb, but not just from the temperature. How does the hubble parameter change with the age of the. Possible role of antimatter galaxies for the stability of. It is an important source of data on the early universe because it is the oldest electromagnetic radiation in the universe, dating to the epoch of. While the spatial size of the entire universe is unknown, it is possible to measure the size of the observable universe, which is currently estimated to be 93 billion lightyears in diameter. Jul 30, 2018 gravity, antimatter and the diracmilne universe. The first observation that one can make from this formula is that it is the hubble parameter that controls that age of the universe, with a correction arising from the matter and energy content. In principle, dark matter means all components of the universe which are not visible. Physics stack exchange is a question and answer site for active researchers, academics and students of physics. Sep 04, 2012 in school ive been told that hubble s constant is the inverse of the age of the universe, this doesnt make sense to me, because in order to arrive at that solution you must first assume that the velocity of a moving body is constant, and that defies the entire point of hubble s law.
Hubble constant and the age of the universe abstract in this paper a new approach to the hubble constant has produced two values one for the expansion of galaxies in the universe at h 0m 38. We can estimate the value of h o from hubble s law. Another way to estimate the age of the universe is to measure the hubble constant. Combining hubble s constant measurement with estimates for the density of the universe, the team determined that the universe is approximately 12 billion years old similar to the oldest stars.
You can actually calculate an estimate for the age of the universe from hubble s law. As the theory goes, when the universe was born it underwent a. How does it influence the expansion of the universe. The current measurement of the age of the universe is around. The chronology of the universe describes the history and future of the universe according to big. Pdf antimatter and antistars in the universe and in the galaxy. Chapter 22 birth of the universe expansion of the universe.
Even with the a known value for the hubble constant, the value projected for the age of the universe is model dependent. The cosmic microwave background radiation is an emission of uniform, black body thermal energy coming from all parts of the sky. In physical cosmology, the age of the universe is the time elapsed since the big bang. One of hubbles initial core purposes was to determine the rate of expansion of the universe, known to astronomers as the hubble constant. Age of the universe was a problem for a einsteinde sitter model, which was solved by. The speed the galaxy moves away from us is directly proportional to the distance from us. Chapter3 hubbles constant and realistic value of the age of the universe 53 if we compare this value in the table starting from hubble period then it looks as. The idea of an accelerating universe comes almost simultaneously with the determination of hubbles constant by one of the hubble space telescope key projects. Note that the present age of the universe follows from the expansion history. So a rough estimate of the age of the universe comes from the hubble time, the inverse of the hubble parameter. The cosmic microwave background cmb radiation tells us the age and composition of the universe and raises new questions that must be answered. Early universe cosmology and the matter antimatter asymmetry author. The hubble constant is a measure of the current expansion rate of the universe.
A nasa hubble space telescope hst view of the magnificent spiral galaxy ngc 4603, the most distant galaxy in which a special class of pulsating. What kinds of tools do astronomers use to calculate the age of the universe, and how can they determine the speed of its expansion. The hubble constant, the matter density, and the scalar spectral index which describes the overdensities and underdensities in the universe are one example of such related parameters. By finding the distance and speed via redshift of various distant galaxies you can produce a graph displaying the linear relationship. Distance measures and the age of the universe in different cosmologies. The cmb tells you the initial conditions and the recipe of the early. Solving the problems of dark matter and matterantimatter asymmetry are the. It tells us how quickly galaxy clusters are flying away from each other today. The hubble constant has not been easy to measure, and the number has changed several times since the 1930s, kuo says. This discovery clears up a nagging paradox that arose from previous age estimates. To test their theories of the course of cosmic reionization, astronomers are probing this epoch in the history of the universe using various methods including telescope observations, something called 21centimeter cosmology and probing the cosmic microwave background. Historical notes the study of the origin, evolution, and eventual fate of the universe has always been debated by philosophers and.
Use your browsers print dialog box to create a pdf. An alternative approach to estimating is the age of the universe is to measure the hubble constant. Age between 23 hubble time and hubble time age 23 hubble time age hubble time a closed universe is younger than an open universe with the same observed hubble constant expansion rate because the higher density in the closed universe has caused more rapid deceleration. Dark matter is a form of matter thought to account for approximately 85% of the matter in the. This fullsky map of the cosmic microwave background radiation cmb, the oldest light in the universe, is based on data collected over the course of 12 months. Here i show how some simple data can be used to plot a graph of hubbles law, from which we can calculate the age of the universe. Cosmology of the 21st century dark matter what is it made of, what are its properties.
Nov 19, 2014 another way to estimate the age of the universe is to measure the hubble constant. When we look around, everything we can see is made of matter. Aug 24, 2018 the cosmic microwave background cmb is thought to be leftover radiation from the big bang, or the time when the universe began. Measuring the age and size of the universe esahubble. The cosmic microwave background cmb, cmbr, in big bang cosmology, is electromagnetic radiation as a remnant from an early stage of the universe, also known as relic radiation. A discrepancy between different measurements of the hubble constant makes scientists question whether something is amiss in. The expansion rate of the universe is called the hubble constant, denoted h. The dynamical result for the age of the universe may be written as. Pdf gravity, antimatter and the diracmilne universe. How to calculate the age of the universe w hubbles. The cmb is a snapshot of the cosmos as it looked only 360,000 years after the big bang as made by the planck space observatory. The best theories available at the time were estimating that the stars at the main sequence turn off in many globular clusters had ages of 15 billion years old or more. If we could take the presently observed expansion and project backward to the beginning of that process, then it would seem reasonable to call that the age of the universe. We know how fast the universe is expanding, because we know the value of hubble s constant h 0.
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