With an initial requirement to make observations a minimum of 5–10 years,Hubble Space Telescope(HST)has continued to operate well for 30 years.It has relied upon five servicing missions to repair and replace essentia...With an initial requirement to make observations a minimum of 5–10 years,Hubble Space Telescope(HST)has continued to operate well for 30 years.It has relied upon five servicing missions to repair and replace essential components.Since the final Space Shuttle mission 10 years ago,it has avoided major breaks in its operation,with the only serious effects of aging in space being a progressive deterioration in the performance of the gyroscopes and sensitivity of the instrument detectors.A number of factors were important in making HST a scientific landmark.Ground-breaking discoveries have been made with HST-the most important being the discovery of cosmic acceleration.When HST operation ceases,future observations in space should be assured with successful operation of major missions now planned by NASA,ESA,and the Chinese and Japanese Space Agencies.展开更多
We constrain cosmological parameters using only Hubble parameter data and quantify the impact of future Hubble parameter measurements on parameter estimation for the most typical dark energy models. We first constrain...We constrain cosmological parameters using only Hubble parameter data and quantify the impact of future Hubble parameter measurements on parameter estimation for the most typical dark energy models. We first constrain cosmological parameters using 52 current Hubble parameter data including the Hubble constant measurement from the Hubble Space Telescope. Then we simulate the baryon acoustic oscillation signals from WFIRST(Wide-Field Infrared Survey Telescope) covering the redshift range of z ∈ [0.5, 2] and the redshift drift data from E-ELT(European Extremely Large Telescope) in the redshift range of z ∈ [2, 5]. It is shown that solely using the current Hubble parameter data could give fairly good constraints on cosmological parameters. Compared to the current Hubble parameter data, with the WFIRST observation the H(z) constraints on dark energy would be improved slightly, while with the E-ELT observation the H(z) constraints on dark energy is enormously improved.展开更多
It is generally accepted that the history of the expansion of the universe can be exactly described by the concordance model, which makes specific predictions about the shape of the Hubble diagram. The redshift-magnit...It is generally accepted that the history of the expansion of the universe can be exactly described by the concordance model, which makes specific predictions about the shape of the Hubble diagram. The redshift-magnitude Hubble diagram in the redshift range z = 0.0104 - 1 seems to confirm this expectation, and it is believed that this conformity is also valid in the high redshift range. However, this belief is not undisputed. Recent work in the high redshift range of up to z = 8.1 has shown that the shape of the Hubble diagram deviates considerably from the predictions made by the Lambda cold dark matter model. These analyses, however, were based on mixed SN1a and gamma ray burst data, and some astronomers argue that this may have biased the results. In this paper, 109 cosmology-independent, calibrated gamma ray burst z/μdata points are used to calculate the Hubble diagram in the range z = 0.034 to z = 8.1. The outcome of this analysis confirms prior results: contrary to expectations, the shape of the Hubble diagram turns out to be exponential, and this is difficult to explain within the framework of the standard model. The cosmological implications of this unexpected result are discussed.展开更多
We compare the Hubble diagram calculated from the observed redshift (RS)/magnitude (μ) data of 280 Supernovae in the RS range of z = 0.0104 to 8.1 with Hubble diagrams inferred on the basis of the exponential tired l...We compare the Hubble diagram calculated from the observed redshift (RS)/magnitude (μ) data of 280 Supernovae in the RS range of z = 0.0104 to 8.1 with Hubble diagrams inferred on the basis of the exponential tired light and the Lambda Cold Dark Matter (ΛCDM) cosmological model. We show that the experimentally measured Hubble diagram follows clearly the exponential photon flight time (tS)/RS relation, whilst the data calculated on the basis of the ΛCDM model exhibit poor agreement with the observed data.展开更多
Purpose: To accurately derive H0 from subatomic constants in abscence of any standard astronomy data. Methods: Recent astronomical data have determined a value of Hubble’s constant to range from 76.9+3.9-3.4+10.0-8.0...Purpose: To accurately derive H0 from subatomic constants in abscence of any standard astronomy data. Methods: Recent astronomical data have determined a value of Hubble’s constant to range from 76.9+3.9-3.4+10.0-8.0 to 67.80 ± 0.77 (km/s)/Mpc. An innovative prediction of H0 is obtained from harmonic properties of the frequency equivalents of neutron, n0, in conjunction with the electron, e;the Bohr radius, α0;and the Rydberg constant, R. These represent integer natural unit sets. The neutron is converted from its frequency equivalent to a dimensionless constant,, where “h” = Planck’s constant, and “s” is measured in seconds. The fundamental frequency, Vf, is the first integer series set . All other atomic data are scaled to Vf as elements in a large, but a countable point set. The present value of H0 is derived and ΩM assumed to be 0. An accurate derivation of H0 is made using a unified power law. The integer set of the first twelve integers N12 {1,2,…,11,12}, and their harmonic fractions exponents of Vf represent the first generation of bosons and particles. Thepartial harmonic fraction, -3/4, is exponent of Vf which represents H0. The partial fraction 3/4 is associated with a component of neutron beta decay kinetic energy. Results: H0 is predicted utilizing a previously published line used to derive Planck time, tp. The power law line of the experimental H0 and tp conforms to the predicted line. Conclusions: H0 can be predicted from subatomic data related to the neutron and hydrogen.展开更多
This paper discusses the “Hubble constant measurement—mystery”. Independent measurements of this cosmic parameter, referred to as <i><span style="font-family:Verdana;">H</span></i>...This paper discusses the “Hubble constant measurement—mystery”. Independent measurements of this cosmic parameter, referred to as <i><span style="font-family:Verdana;">H</span></i><sub><span style="font-family:Verdana;">0</span></sub><span style="font-family:Verdana;"> in abbreviated form, have all led to different values, with the highest value ≈ 74 km<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">·</span>s</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;"><span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">·</span>Mpc</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;"> and the lowest ≈ 67 km<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">·</span>s</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;"><span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">·</span>Mpc</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;">, where km denotes kilometer, s second and Mpc</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;"> megaparsec. These measurements have mainly been obtained with space telescopes. Apparently, up to now there was no way to explain the differences. However, previously published studies seem to regard the problem of the different measurement results for </span><i><span style="font-family:Verdana;">H</span></i><sub><span style="font-family:Verdana;">0</span></sub><span style="font-family:Verdana;"> [</span><span style="font-family:Verdana;"><a href="#ref1">1</a>,</span><b><span style="font-family:Verdana;"> </span></b><span style="font-family:Verdana;"><a href="#ref2">2</a></span><span style="font-family:Verdana;">]. I have shown that due to a symmetrical expansion of the Minkowski space (SMS), each respective frame of reference for an observer, who rests in the zero point of the frame, is converted into a state of apparent rest relative to the cosmic microwave background (CMB) radiation. This SMS-relativistic effect also seems to be responsible for the different measurement results of the Hubble constant, especially through space telescopes.</span>展开更多
Assessment of the Hubble parameter as an indicator of the expansion rate of the universe holds a central position in the field of astronomy. From its initial estimate of about 500 km<span style="white-space:no...Assessment of the Hubble parameter as an indicator of the expansion rate of the universe holds a central position in the field of astronomy. From its initial estimate of about 500 km<span style="white-space:nowrap;">⋅</span>sec<sup>-1</sup><span style="white-space:nowrap;">⋅</span>parsc<sup>-1</sup>, this value had been steadily amended as the observational tools became more accurate and precise. Despite this, a gap remains between the value of observations relating to local and nonlocal estimations of the Hubble parameter that gave rise to what became known as the Hubble tension. This tension is addressed here while dealing with space fabric as a cosmological fluid that undergoes transition.展开更多
Based on an analysis of 280 Type SNIa supernovae and gamma-ray bursts redshifts in the range of z = 0.0104 - 8.1 the Hubble diagram is shown to follow a strictly exponential slope predicting an exponentially expanding...Based on an analysis of 280 Type SNIa supernovae and gamma-ray bursts redshifts in the range of z = 0.0104 - 8.1 the Hubble diagram is shown to follow a strictly exponential slope predicting an exponentially expanding or static universe. At redshifts > 2 - 3 ΛCDM models show a poor agreement with the observed data. Based on the results presented in this paper, the Hubble diagram test does not necessarily support the idea of expansion according to the big-bang concordance model.展开更多
Purpose: The cosmic microwave background radiation, CMB, is fundamental to observational cosmology, and is believed to be a remnant from the Big Bang. The CMB, Planck time, t<sub>P</sub>, and the Hubble co...Purpose: The cosmic microwave background radiation, CMB, is fundamental to observational cosmology, and is believed to be a remnant from the Big Bang. The CMB, Planck time, t<sub>P</sub>, and the Hubble constant, H<sub>0</sub>, are important cosmologic constants. The goal is to accurately derive and demonstrate the inter-relationships of the CMB peak spectral radiance frequency, t<sub>P</sub>, and H<sub>0</sub> from neutron and hydrogen quantum data only. Methods: The harmonic neutron hypothesis, HNH, evaluates physical phenomena within a finite consecutive integer and exponential power law harmonic fraction series that are scaled by a fundamental frequency of the neutron as the exponent base. The CMB and the H<sub>0</sub> are derived from a previously published method used to derive t<sub>P</sub>. Their associated integer exponents are respectively +1/2, −3/4, and −128/35. Results: Precise mathematical relationships of these three constants are demonstrated. All of the derived values are within their known observational values. The derived and known values are: ν<sub>CMB</sub>, 160.041737 (06) × 10<sup>9</sup> Hz, ~160 × 10<sup>9</sup> Hz;2.72519 K, 2.72548 ± 0.00057 K, H<sub>0</sub> 2.29726666 (11) × 10<sup>−18</sup> s<sup>−1</sup>, ~2.3 × 10<sup>−18</sup> s<sup>−1</sup>;and t<sub>P</sub> 5.3911418 (3) × 10<sup>−44</sup> s, 5.39106 (32) × 10<sup>−44</sup> s. Conclusion: The cosmic fundamental constants t<sub>P</sub>, H<sub>0</sub>, and CMB are mathematically inter-related constants all defined by gravity. They are also directly derivable from the quantum properties of the neutron and hydrogen within a harmonic power law.展开更多
General Relativity implies an expanding Universe from a singularity, the so-called Big Bang. The rate of expansion is the Hubble constant. There are two major ways of measuring the expansion of the Universe: through t...General Relativity implies an expanding Universe from a singularity, the so-called Big Bang. The rate of expansion is the Hubble constant. There are two major ways of measuring the expansion of the Universe: through the cosmic distance ladder and through looking at the signals originated from the beginning of the Universe. These two methods give quite different results for the Hubble constant. Hence, the Universe doesn’t expand. The solution to this problem is the theory of gravitation in flat space-time where space isn’t expanding. All the results of gravitation for weak fields of this theory agree with those of General Relativity to measurable accuracy whereas at the beginning of the Universe the results of both theories are quite different, i.e. no singularity by gravitation in flat space-time and non-expanding universe, and a Big Bang (singularity) by General Relativity.展开更多
The results of measurements of the Hubble constant H<sub>0</sub>, which characterizes the expansion rate of the universe, show that the values of H<sub>0</sub> vary significantly depending on M...The results of measurements of the Hubble constant H<sub>0</sub>, which characterizes the expansion rate of the universe, show that the values of H<sub>0</sub> vary significantly depending on Methodology. The disagreement in the values of H<sub>0</sub> obtained by the various teams far exceeds the standard uncertainties provided with the values. This discrepancy is called the Hubble Tension. In this paper, we discuss Macrostructures of the World (Superclusters and Galaxies);explain their Origin and Evolution in frames of the developed Hypersphere World-Universe Model (WUM), which is an alternative to the prevailing Big Bang Model (BBM) [1];and provide the explanation of the Hubble Tension. The main difference between WUM and BBM is: Instead of the Infinite Homogeneous and Isotropic Universe around the Initial Singularity in BBM, in WUM, the 3D Finite Boundless World (a Hypersphere) presents a Patchwork Quilt of different Luminous Superclusters (10<sup>3</sup>), which emerged in various places of the World at different Cosmological times. In WUM, the Medium of the World is Homogeneous and Isotropic. The distribution of Macroobjects in the World is spatially Inhomogeneous and Anisotropic and temporally Non-simultaneous.展开更多
In this work,we use the most recent publicly available type Ⅰa supernova(SNIa) compilations and H(z) data.A well formulated cosmological model based on Bianchi type Ⅰ(BI) metric is implemented in the presence of the...In this work,we use the most recent publicly available type Ⅰa supernova(SNIa) compilations and H(z) data.A well formulated cosmological model based on Bianchi type Ⅰ(BI) metric is implemented in the presence of the Ricci dark energy model.Using the maximum likelihood technique,we estimate the present value of Hubble's constant H_(0)=70.339±0.743,matter density parameter Ω_(m_(0))=0.297±0.031,anisotropy parameter Ω_(σ_(0))=-0.004 01 ± 0.001 07 within 1σ′ confidence level by bounding our derived model with recent joint Pantheon and H(z)data.We have constrained the present value of the equation of state parameter as ω_(de)=-1.17 joint with the observational data.The present value of the deceleration parameter of the Universe in the derived model is obtained as q_(0)=-0.749_(-0.086)^(+0.076).Transition redshift is also derived as z_(tr)~0.551 with the recent observations(Pantheon+H(z)) datasets.Finally,we compare the anisotropy effects on the evolution of H(z) for the proposed model under consideration with different observational datasets.展开更多
In coastal sea areas with the bimodal Ochi-Hubble wave spectrum, such as parts of the China Sea and Indian Ocean,wave energy is the superposition of wind wave and swell. Traditional heaving buoy wave energy converters...In coastal sea areas with the bimodal Ochi-Hubble wave spectrum, such as parts of the China Sea and Indian Ocean,wave energy is the superposition of wind wave and swell. Traditional heaving buoy wave energy converters developed with narrowband wave spectrums suffer from big energy loss in these areas, leading to lower power absorption efficiency and higher generating costs. In contrast, multi-freedom buoy has different resonant frequencies and maximal power capture wave frequencies in different degrees of freedom(DOFs). Therefore, this study proposed using two DOFs to capture the energy of wind wave and swell correspondingly. A heave and pitch buoy model was established by potential flow theory and validated by experimental data. Coupling effect on the motion and power absorption, power capture frequency distribution and power absorption with different linear power takeoff system damping coefficients were analyzed to reveal the hydrodynamic response and the power performance of the two DOFs. The results indicate that by using heave and pitch DOFs, the wave energy components of wind wave and swell were captured in a targeted manner. It demonstrates that the 2-DOF buoy is an effective tool to avoid the energy loss and realize the efficient power absorption in coastal sea areas with bimodal Ochi-Hubble waves.展开更多
The present study deals with a spatially homogeneous and anisotropic Bianehi-I cosmological models representing massive strings with magnetic field and decaying vacuum energy density A. The energy-momentum tensor, as ...The present study deals with a spatially homogeneous and anisotropic Bianehi-I cosmological models representing massive strings with magnetic field and decaying vacuum energy density A. The energy-momentum tensor, as formulated by Letelier （1983）, has been used to construct massive string cosmological models for which we assume the expansion scalar in the models is proportional to one of the components of shear tensor. The Einstein＇s field equations have been solved by applying a variation law for generalized Hubble＇s parameter in Bianchi-I space-time. The variation law for Hubble＇s parameter generates two types of solutions for the average scale factor, one is of power-law type and other is of the exponential form. Using these two forms, Einstein＇s field equations are solved separately that correspond to expanding singular and non-singular models of the universe respectively. We have made a comparative study of accelerating and decelerating models in the presence of string scenario. The study reveals that massive strings dominate in the decelerating universe whereas strings dominate in the accelerating universe. The strings eventually disappear from the universe for sufficiently large times, which is in agreement with current astronomical observations. The cosmological constant A is found to be a positive decreasing function of time which is corroborated by results from recent supernovae Ia observations. The physical and geometric properties of the models have been also discussed in detail.展开更多
Different measurements of the Hubble constant(H_(0))are not consistent,and a tension between the CMB based methods and cosmic distance ladder based methods has been observed.Measurements from various distance based me...Different measurements of the Hubble constant(H_(0))are not consistent,and a tension between the CMB based methods and cosmic distance ladder based methods has been observed.Measurements from various distance based methods are also inconsistent.To aggravate the problem,the same cosmological probe(TypeⅠa SNe for instance)calibrated through different methods also provides different values of H_(0).We compare various distance ladder based methods through the already available unique data obtained from the Hubble Space Telescope(HST).Our analysis is based on parametric(t-test)as well as non-parametric statistical methods such as the Mann-Whitney U test and Kolmogorov-Smirnov test.Our results show that different methods provide different values of H_(0) and the differences are statistically significant.The biases in the calibration would not account for these differences as the data have been taken from a single telescope with a common calibration scheme.The unknown physical effects or issues with the empirical relations of distance measurement from different probes could give rise to these differences.展开更多
文摘With an initial requirement to make observations a minimum of 5–10 years,Hubble Space Telescope(HST)has continued to operate well for 30 years.It has relied upon five servicing missions to repair and replace essential components.Since the final Space Shuttle mission 10 years ago,it has avoided major breaks in its operation,with the only serious effects of aging in space being a progressive deterioration in the performance of the gyroscopes and sensitivity of the instrument detectors.A number of factors were important in making HST a scientific landmark.Ground-breaking discoveries have been made with HST-the most important being the discovery of cosmic acceleration.When HST operation ceases,future observations in space should be assured with successful operation of major missions now planned by NASA,ESA,and the Chinese and Japanese Space Agencies.
基金Supported by the National Natural Science Foundation of China under Grant Nos.11522540,11690021,11375153,11675145the National Program for Support of Top-Notch Young Professionalsthe 2016 Program for Postdoctoral Fellowship of Zhejiang Province
文摘We constrain cosmological parameters using only Hubble parameter data and quantify the impact of future Hubble parameter measurements on parameter estimation for the most typical dark energy models. We first constrain cosmological parameters using 52 current Hubble parameter data including the Hubble constant measurement from the Hubble Space Telescope. Then we simulate the baryon acoustic oscillation signals from WFIRST(Wide-Field Infrared Survey Telescope) covering the redshift range of z ∈ [0.5, 2] and the redshift drift data from E-ELT(European Extremely Large Telescope) in the redshift range of z ∈ [2, 5]. It is shown that solely using the current Hubble parameter data could give fairly good constraints on cosmological parameters. Compared to the current Hubble parameter data, with the WFIRST observation the H(z) constraints on dark energy would be improved slightly, while with the E-ELT observation the H(z) constraints on dark energy is enormously improved.
文摘It is generally accepted that the history of the expansion of the universe can be exactly described by the concordance model, which makes specific predictions about the shape of the Hubble diagram. The redshift-magnitude Hubble diagram in the redshift range z = 0.0104 - 1 seems to confirm this expectation, and it is believed that this conformity is also valid in the high redshift range. However, this belief is not undisputed. Recent work in the high redshift range of up to z = 8.1 has shown that the shape of the Hubble diagram deviates considerably from the predictions made by the Lambda cold dark matter model. These analyses, however, were based on mixed SN1a and gamma ray burst data, and some astronomers argue that this may have biased the results. In this paper, 109 cosmology-independent, calibrated gamma ray burst z/μdata points are used to calculate the Hubble diagram in the range z = 0.034 to z = 8.1. The outcome of this analysis confirms prior results: contrary to expectations, the shape of the Hubble diagram turns out to be exponential, and this is difficult to explain within the framework of the standard model. The cosmological implications of this unexpected result are discussed.
文摘We compare the Hubble diagram calculated from the observed redshift (RS)/magnitude (μ) data of 280 Supernovae in the RS range of z = 0.0104 to 8.1 with Hubble diagrams inferred on the basis of the exponential tired light and the Lambda Cold Dark Matter (ΛCDM) cosmological model. We show that the experimentally measured Hubble diagram follows clearly the exponential photon flight time (tS)/RS relation, whilst the data calculated on the basis of the ΛCDM model exhibit poor agreement with the observed data.
文摘Purpose: To accurately derive H0 from subatomic constants in abscence of any standard astronomy data. Methods: Recent astronomical data have determined a value of Hubble’s constant to range from 76.9+3.9-3.4+10.0-8.0 to 67.80 ± 0.77 (km/s)/Mpc. An innovative prediction of H0 is obtained from harmonic properties of the frequency equivalents of neutron, n0, in conjunction with the electron, e;the Bohr radius, α0;and the Rydberg constant, R. These represent integer natural unit sets. The neutron is converted from its frequency equivalent to a dimensionless constant,, where “h” = Planck’s constant, and “s” is measured in seconds. The fundamental frequency, Vf, is the first integer series set . All other atomic data are scaled to Vf as elements in a large, but a countable point set. The present value of H0 is derived and ΩM assumed to be 0. An accurate derivation of H0 is made using a unified power law. The integer set of the first twelve integers N12 {1,2,…,11,12}, and their harmonic fractions exponents of Vf represent the first generation of bosons and particles. Thepartial harmonic fraction, -3/4, is exponent of Vf which represents H0. The partial fraction 3/4 is associated with a component of neutron beta decay kinetic energy. Results: H0 is predicted utilizing a previously published line used to derive Planck time, tp. The power law line of the experimental H0 and tp conforms to the predicted line. Conclusions: H0 can be predicted from subatomic data related to the neutron and hydrogen.
文摘This paper discusses the “Hubble constant measurement—mystery”. Independent measurements of this cosmic parameter, referred to as <i><span style="font-family:Verdana;">H</span></i><sub><span style="font-family:Verdana;">0</span></sub><span style="font-family:Verdana;"> in abbreviated form, have all led to different values, with the highest value ≈ 74 km<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">·</span>s</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;"><span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">·</span>Mpc</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;"> and the lowest ≈ 67 km<span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">·</span>s</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;"><span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">·</span>Mpc</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;">, where km denotes kilometer, s second and Mpc</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;"> megaparsec. These measurements have mainly been obtained with space telescopes. Apparently, up to now there was no way to explain the differences. However, previously published studies seem to regard the problem of the different measurement results for </span><i><span style="font-family:Verdana;">H</span></i><sub><span style="font-family:Verdana;">0</span></sub><span style="font-family:Verdana;"> [</span><span style="font-family:Verdana;"><a href="#ref1">1</a>,</span><b><span style="font-family:Verdana;"> </span></b><span style="font-family:Verdana;"><a href="#ref2">2</a></span><span style="font-family:Verdana;">]. I have shown that due to a symmetrical expansion of the Minkowski space (SMS), each respective frame of reference for an observer, who rests in the zero point of the frame, is converted into a state of apparent rest relative to the cosmic microwave background (CMB) radiation. This SMS-relativistic effect also seems to be responsible for the different measurement results of the Hubble constant, especially through space telescopes.</span>
文摘Assessment of the Hubble parameter as an indicator of the expansion rate of the universe holds a central position in the field of astronomy. From its initial estimate of about 500 km<span style="white-space:nowrap;">⋅</span>sec<sup>-1</sup><span style="white-space:nowrap;">⋅</span>parsc<sup>-1</sup>, this value had been steadily amended as the observational tools became more accurate and precise. Despite this, a gap remains between the value of observations relating to local and nonlocal estimations of the Hubble parameter that gave rise to what became known as the Hubble tension. This tension is addressed here while dealing with space fabric as a cosmological fluid that undergoes transition.
文摘Based on an analysis of 280 Type SNIa supernovae and gamma-ray bursts redshifts in the range of z = 0.0104 - 8.1 the Hubble diagram is shown to follow a strictly exponential slope predicting an exponentially expanding or static universe. At redshifts > 2 - 3 ΛCDM models show a poor agreement with the observed data. Based on the results presented in this paper, the Hubble diagram test does not necessarily support the idea of expansion according to the big-bang concordance model.
文摘Purpose: The cosmic microwave background radiation, CMB, is fundamental to observational cosmology, and is believed to be a remnant from the Big Bang. The CMB, Planck time, t<sub>P</sub>, and the Hubble constant, H<sub>0</sub>, are important cosmologic constants. The goal is to accurately derive and demonstrate the inter-relationships of the CMB peak spectral radiance frequency, t<sub>P</sub>, and H<sub>0</sub> from neutron and hydrogen quantum data only. Methods: The harmonic neutron hypothesis, HNH, evaluates physical phenomena within a finite consecutive integer and exponential power law harmonic fraction series that are scaled by a fundamental frequency of the neutron as the exponent base. The CMB and the H<sub>0</sub> are derived from a previously published method used to derive t<sub>P</sub>. Their associated integer exponents are respectively +1/2, −3/4, and −128/35. Results: Precise mathematical relationships of these three constants are demonstrated. All of the derived values are within their known observational values. The derived and known values are: ν<sub>CMB</sub>, 160.041737 (06) × 10<sup>9</sup> Hz, ~160 × 10<sup>9</sup> Hz;2.72519 K, 2.72548 ± 0.00057 K, H<sub>0</sub> 2.29726666 (11) × 10<sup>−18</sup> s<sup>−1</sup>, ~2.3 × 10<sup>−18</sup> s<sup>−1</sup>;and t<sub>P</sub> 5.3911418 (3) × 10<sup>−44</sup> s, 5.39106 (32) × 10<sup>−44</sup> s. Conclusion: The cosmic fundamental constants t<sub>P</sub>, H<sub>0</sub>, and CMB are mathematically inter-related constants all defined by gravity. They are also directly derivable from the quantum properties of the neutron and hydrogen within a harmonic power law.
文摘General Relativity implies an expanding Universe from a singularity, the so-called Big Bang. The rate of expansion is the Hubble constant. There are two major ways of measuring the expansion of the Universe: through the cosmic distance ladder and through looking at the signals originated from the beginning of the Universe. These two methods give quite different results for the Hubble constant. Hence, the Universe doesn’t expand. The solution to this problem is the theory of gravitation in flat space-time where space isn’t expanding. All the results of gravitation for weak fields of this theory agree with those of General Relativity to measurable accuracy whereas at the beginning of the Universe the results of both theories are quite different, i.e. no singularity by gravitation in flat space-time and non-expanding universe, and a Big Bang (singularity) by General Relativity.
文摘The results of measurements of the Hubble constant H<sub>0</sub>, which characterizes the expansion rate of the universe, show that the values of H<sub>0</sub> vary significantly depending on Methodology. The disagreement in the values of H<sub>0</sub> obtained by the various teams far exceeds the standard uncertainties provided with the values. This discrepancy is called the Hubble Tension. In this paper, we discuss Macrostructures of the World (Superclusters and Galaxies);explain their Origin and Evolution in frames of the developed Hypersphere World-Universe Model (WUM), which is an alternative to the prevailing Big Bang Model (BBM) [1];and provide the explanation of the Hubble Tension. The main difference between WUM and BBM is: Instead of the Infinite Homogeneous and Isotropic Universe around the Initial Singularity in BBM, in WUM, the 3D Finite Boundless World (a Hypersphere) presents a Patchwork Quilt of different Luminous Superclusters (10<sup>3</sup>), which emerged in various places of the World at different Cosmological times. In WUM, the Medium of the World is Homogeneous and Isotropic. The distribution of Macroobjects in the World is spatially Inhomogeneous and Anisotropic and temporally Non-simultaneous.
文摘In this work,we use the most recent publicly available type Ⅰa supernova(SNIa) compilations and H(z) data.A well formulated cosmological model based on Bianchi type Ⅰ(BI) metric is implemented in the presence of the Ricci dark energy model.Using the maximum likelihood technique,we estimate the present value of Hubble's constant H_(0)=70.339±0.743,matter density parameter Ω_(m_(0))=0.297±0.031,anisotropy parameter Ω_(σ_(0))=-0.004 01 ± 0.001 07 within 1σ′ confidence level by bounding our derived model with recent joint Pantheon and H(z)data.We have constrained the present value of the equation of state parameter as ω_(de)=-1.17 joint with the observational data.The present value of the deceleration parameter of the Universe in the derived model is obtained as q_(0)=-0.749_(-0.086)^(+0.076).Transition redshift is also derived as z_(tr)~0.551 with the recent observations(Pantheon+H(z)) datasets.Finally,we compare the anisotropy effects on the evolution of H(z) for the proposed model under consideration with different observational datasets.
基金financially supported by the Major Scientific and Technological Innovation Projects in Shandong Province (Grant No.2018CXGC0104)the National Key Research and Development Program of China (Grant No. 2016YFE0205700)+1 种基金the National Natural Science Foundation of China (Grant No. U1706230)the Qingdao Postdoctoral Applied Research Project
文摘In coastal sea areas with the bimodal Ochi-Hubble wave spectrum, such as parts of the China Sea and Indian Ocean,wave energy is the superposition of wind wave and swell. Traditional heaving buoy wave energy converters developed with narrowband wave spectrums suffer from big energy loss in these areas, leading to lower power absorption efficiency and higher generating costs. In contrast, multi-freedom buoy has different resonant frequencies and maximal power capture wave frequencies in different degrees of freedom(DOFs). Therefore, this study proposed using two DOFs to capture the energy of wind wave and swell correspondingly. A heave and pitch buoy model was established by potential flow theory and validated by experimental data. Coupling effect on the motion and power absorption, power capture frequency distribution and power absorption with different linear power takeoff system damping coefficients were analyzed to reveal the hydrodynamic response and the power performance of the two DOFs. The results indicate that by using heave and pitch DOFs, the wave energy components of wind wave and swell were captured in a targeted manner. It demonstrates that the 2-DOF buoy is an effective tool to avoid the energy loss and realize the efficient power absorption in coastal sea areas with bimodal Ochi-Hubble waves.
基金Supported in part by the Council of Science and Technology,Uttar Pradesh,India
文摘The present study deals with a spatially homogeneous and anisotropic Bianehi-I cosmological models representing massive strings with magnetic field and decaying vacuum energy density A. The energy-momentum tensor, as formulated by Letelier （1983）, has been used to construct massive string cosmological models for which we assume the expansion scalar in the models is proportional to one of the components of shear tensor. The Einstein＇s field equations have been solved by applying a variation law for generalized Hubble＇s parameter in Bianchi-I space-time. The variation law for Hubble＇s parameter generates two types of solutions for the average scale factor, one is of power-law type and other is of the exponential form. Using these two forms, Einstein＇s field equations are solved separately that correspond to expanding singular and non-singular models of the universe respectively. We have made a comparative study of accelerating and decelerating models in the presence of string scenario. The study reveals that massive strings dominate in the decelerating universe whereas strings dominate in the accelerating universe. The strings eventually disappear from the universe for sufficiently large times, which is in agreement with current astronomical observations. The cosmological constant A is found to be a positive decreasing function of time which is corroborated by results from recent supernovae Ia observations. The physical and geometric properties of the models have been also discussed in detail.
文摘Different measurements of the Hubble constant(H_(0))are not consistent,and a tension between the CMB based methods and cosmic distance ladder based methods has been observed.Measurements from various distance based methods are also inconsistent.To aggravate the problem,the same cosmological probe(TypeⅠa SNe for instance)calibrated through different methods also provides different values of H_(0).We compare various distance ladder based methods through the already available unique data obtained from the Hubble Space Telescope(HST).Our analysis is based on parametric(t-test)as well as non-parametric statistical methods such as the Mann-Whitney U test and Kolmogorov-Smirnov test.Our results show that different methods provide different values of H_(0) and the differences are statistically significant.The biases in the calibration would not account for these differences as the data have been taken from a single telescope with a common calibration scheme.The unknown physical effects or issues with the empirical relations of distance measurement from different probes could give rise to these differences.
