The Age of the Universe and its Measurement

Current wisdom in cosmology has it that the Universe is about 13.8 billions year old. Statements about the age of the Universe are not just difficult to confirm, but also carry a lot of presuppositions. The aim of this talk is to make explicit these presuppositions, to discuss their significance and to trace the implications for an emipirical investigation of the age of the Universe.

Constructed Response Answers in a Multiple-Choice Universe

A scheme is introduced which allows computer readable multiple choice forms used in traditional examinations to be employed for constructed response items.

Financial Liberalization and Inflationary Dynamics in the Context of a Small Open Economy

The paper develops a short-run model of a small open financially repressed economy characterized by unorganized money markets, capital good imports, capital mobility, wage indexation, and flexible exchange rates. The analysis shows that financial liberalization, in the form of an increased rate of interest on deposits and tight monetary policy, unambiguously and unconditionally causes deflation. Moreover, the results do not depend on the degree of capital mobility and structure of wage setting. The paper recommends that a small open developing economy should deregulate interest rates and tighten monetary policy if reducing inflation is a priority. The pre-requisite for such a policy, however, requires the establishment of a flexible exchange rate regime.

Quantization of the universe as a black hole.

It has been shown that black holes can be quantized by using Bohr’s idea of quantizing the motion of an electron inside the atom. We apply these ideas to the universe as a whole. This approach reinforces the suggestion that it may be a way to unify gravity with quantum theory.

Evidence for a disaggregation of the universe.

Combining the kinematical definitions of the two dimensionless parameters, the deceleration q(x) and the Hubble t 0 H(x), we get a differential equation (where x=t/t 0 is the age of the universe relative to its present value t 0). First integration gives the function H(x). The present values of the Hubble parameter H(1) [approximately t 0 H(1)≈1], and the deceleration parameter [approximately q(1)≈−0.5], determine the function H(x). A second integration gives the cosmological scale factor a(x). Differentiation of a(x) gives the speed of expansion of the universe. The evolution of the universe that results from our approach is: an initial extremely fast exponential expansion (inflation), followed by an almost linear expansion (first decelerated, and later accelerated). For the future, at approximately t≈3t 0 there is a final exponential expansion, a second inflation that produces a disaggregation of the universe to infinity. We find the necessary and sufficient conditions for this disaggregation to occur. The precise value of the final age is given only with one parameter: the present value of the deceleration parameter [q(1)≈−0.5]. This emerging picture of the history of the universe represents an important challenge, an opportunity for the immediate research on the Universe. These conclusions have been elaborated without the use of any particular cosmological model of the universe

Cosmos : a sketch of a physical description of the universe / By Alexander von Humboldt ; Translated from the German by E.C. Otté.

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Cosmos : a sketch of a physical description of the universe / By Alexander von Humboldt ; Translated from the German by E.C. Otté.

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Cosmos : a sketch of a physical description of the universe / By Alexander von Humboldt ; Translated from the German by E.C. Otté.

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Cosmos : a sketch of a physical description of the universe / By Alexander von Humboldt ; Translated from the German by E.C. Otté.

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Cosmos : a sketch of a physical description of the universe / By Alexander von Humboldt ; Translated from the German by E.C. Otté.

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A lightweight universe?

How much matter is there in the universe? Does the universe have the critical density needed to stop its expansion, or is the universe underweight and destined to expand forever? We show that several independent measures, especially those utilizing the largest bound systems known—clusters of galaxies—all indicate that the mass-density of the universe is insufficient to halt the expansion. A promising new method, the evolution of the number density of clusters with time, provides the most powerful indication so far that the universe has a subcritical density. We show that different techniques reveal a consistent picture of a lightweight universe with only ∼20–30% of the critical density. Thus, the universe may expand forever.

Supernovae, an accelerating universe and the cosmological constant

Observations of supernova explosions halfway back to the Big Bang give plausible evidence that the expansion of the universe has been accelerating since that epoch, approximately 8 billion years ago and suggest that energy associated with the vacuum itself may be responsible for the acceleration.