Advances in Astronomy最新文献_第7页

Oceans, Lakes, and Stromatolites on Mars 火星上的海洋、湖泊和叠层石

IF 1.4 4区物理与天体物理

Advances in Astronomy Pub Date : 2020-10-17 DOI: 10.1155/2020/6959532

R. Joseph, O. Planchon, N. Duxbury, K. Latif, G. Kidron, L. Consorti, R. Armstrong, Carl H. Gibson, Rudolph E. Schild

{"title":"Oceans, Lakes, and Stromatolites on Mars","authors":"R. Joseph, O. Planchon, N. Duxbury, K. Latif, G. Kidron, L. Consorti, R. Armstrong, Carl H. Gibson, Rudolph E. Schild","doi":"10.1155/2020/6959532","DOIUrl":"https://doi.org/10.1155/2020/6959532","url":null,"abstract":"Billions of years ago, the Northern Hemisphere of Mars may have been covered by at least one ocean and thousands of lakes and rivers. These findings, based initially on telescopic observations and images by the Mariner and Viking missions, led investigators to hypothesize that stromatolite fashioning cyanobacteria may have proliferated in the surface waters, and life may have been successfully transferred between Earth and Mars via tons of debris ejected into the space following bolide impact. Studies conducted by NASA’s robotic rovers also indicate that Mars was wet and habitable and may have been inhabited in the ancient past. It has been hypothesized that Mars subsequently lost its magnetic field, oceans, and atmosphere when bolides negatively impacted its geodynamo and that the remnants of the Martian seas began to evaporate and became frozen beneath the surface. As reviewed here, twenty-five investigators have published evidence of Martian sedimentary structures that resemble microbial mats and stromatolites, which may have been constructed billions of years ago on ancient lake shores and in receding bodies of water, although if these formations are abiotic or biotic is unknown. These findings parallel the construction of the first stromatolites on Earth. The evidence reviewed here does not prove but supports the hypothesis that ancient Mars had oceans (as well as lakes) and was habitable and inhabited, and life may have been transferred between Earth and Mars billions of years ago due to powerful solar winds and life-bearing ejecta propelled into the space following the bolide impact.","PeriodicalId":48962,"journal":{"name":"Advances in Astronomy","volume":"2020 1","pages":"6959532"},"PeriodicalIF":1.4,"publicationDate":"2020-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2020/6959532","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46729476","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 8

Nucleonic Direct Urca Processes and Cooling of the Massive Neutron Star by Antikaon Condensations 核子直接Urca过程与反介子凝聚的大质量中子星冷却

IF 1.4 4区物理与天体物理

Advances in Astronomy Pub Date : 2020-10-17 DOI: 10.1155/2020/6146913

Yan Xu, W. Ding, Cheng-zhi Liu, J. Han

引用次数: 0

The Slow Spinning Motion of a Rigid Body in Newtonian Field and External Torque 刚体在牛顿场和外扭矩下的慢旋转运动

IF 1.4 4区物理与天体物理

Advances in Astronomy Pub Date : 2020-10-15 DOI: 10.1155/2020/4179590

A. I. Ismail

引用次数: 3

Solving a Problem of Rotary Motion for a Heavy Solid Using the Large Parameter Method 用大参数法求解重固体旋转运动问题

IF 1.4 4区物理与天体物理

Advances in Astronomy Pub Date : 2020-09-01 DOI: 10.1155/2020/2764867

A. I. Ismail

引用次数: 12

Balanced Low Earth Satellite Orbits 平衡低地球卫星轨道

IF 1.4 4区物理与天体物理

Advances in Astronomy Pub Date : 2020-08-19 DOI: 10.1155/2020/7421396

A. Mostafa, M. H. El Dewaik

引用次数: 0

The Existence and Effect of Dark Energy Redshift on Cosmological Age 暗能量红移的存在及其对宇宙年龄的影响

IF 1.4 4区物理与天体物理

Advances in Astronomy Pub Date : 2020-08-11 DOI: 10.1155/2020/2436965

R. Storti

引用次数: 1

Central Configurations and Action Minimizing Orbits in Kite Four-Body Problem 风筝三体问题中的中心构型和最小作用轨道

IF 1.4 4区物理与天体物理

Advances in Astronomy Pub Date : 2020-08-01 DOI: 10.1155/2020/5263750

B. Benhammouda, A. Mansur, M. Shoaib, I. Szücs-Csillik, D. Offin

引用次数: 1

Analysis and Research on the Centimeter Band Receiver Amplitude Calibration Method 厘米波段接收机幅度标定方法的分析与研究

IF 1.4 4区物理与天体物理

Advances in Astronomy Pub Date : 2020-07-03 DOI: 10.1155/2020/8484610

Kai Wang, Mao-zheng Chen, Jun Ma, X. Duan, Yang Wang, Liang Cao, Hao Yan, B. Xiang

{"title":"Analysis and Research on the Centimeter Band Receiver Amplitude Calibration Method","authors":"Kai Wang, Mao-zheng Chen, Jun Ma, X. Duan, Yang Wang, Liang Cao, Hao Yan, B. Xiang","doi":"10.1155/2020/8484610","DOIUrl":"https://doi.org/10.1155/2020/8484610","url":null,"abstract":"The receiver is a signal receiving device in a radio telescope system. As an important parameter to characterize the receiver performance, noise temperature is very practical to calibrate accurately. The traditional receiver noise temperature calibration method is the cold and ambient load method. Through the establishment of K-band ambient receiver, and its amplitude calibration test platform of the cold and ambient load method, chopper wheel method, and ambient and hot load method, comparison and analysis of the above three methods were carried out. The test and calculation results show that the test accuracy of the cold and ambient load method is about 1.3%, that of the chopper wheel method (nonlow elevation) is about 3%, and that of the ambient and hot load method is about 9%. The test accuracy of the ambient and hot load method is slightly lower than that of the above two methods. The analysis is mainly due to the uncertainty of the hot load temperature and the small temperature difference between the two loads, which leads to the deterioration of the overall accuracy. But the advantage is that the method can perform real-time calibration in the process of observation, and it is easier to implement than the traditional cold and ambient load method. The results of noise temperature measurement are compared with those of theoretical calculation, the error is basically within 10%, and it can satisfy the demand of the noise temperature test. In the future, we expect that on the basis of increasing the hot load temperature, further experiments were carried out on the thermostatic treatment of hot load and the accuracy of temperature acquisition, and finally we hope that this method can better meet the testing requirements of receiver noise temperature and radio source amplitude calibration.","PeriodicalId":48962,"journal":{"name":"Advances in Astronomy","volume":"2020 1","pages":"1-10"},"PeriodicalIF":1.4,"publicationDate":"2020-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1155/2020/8484610","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43422010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Introducing Our New Chief Editor 介绍我们的新主编

IF 1.4 4区物理与天体物理

Advances in Astronomy Pub Date : 2020-06-30 DOI: 10.1155/2020/7382029

J. Trigo-Rodríguez

引用次数: 0

Astronomical Massive Data Processing Technology 天文海量数据处理技术

IF 1.4 4区物理与天体物理

Advances in Astronomy Pub Date : 2020-05-01 DOI: 10.1155/2020/6848935

Feng Wang, W. Cao, D. Bastieri, J. Fan, Chenzhou Cui

引用次数: 0