Ole Roemer, Who Started It All

Lightspeed ◽  
2019 ◽  
pp. 18-26
Author(s):  
John C. H. Spence
Keyword(s):  
Life Story ◽  
The Sun ◽  
Speed Of Light ◽  
The Earth ◽  
At Home

The story of the first measurement of the speed of light by Ole Roemer in 1676. Galileo had discovered the moons of Jupiter with his new telescope, and proposed using observations of their eclipse every forty-two hours as a universal clock for our planet, since they could be seen from practically anywhere. This would keep track of the time at home, and so give a traveller his or her local longitude. (The King of Spain had offered a prize for longitude determination to avoid disasterous shipwrecks.) Roemer noticed that the eclipses were sometimes a little late, which he concluded was due to the time it took light to get from Saturn to Earth and the movement of the Earth between eclipses. His estimate of the time for light to travel from the Sun to Earth was quite accurate. Roemer’s remarkable life story and many other achievements are told.

James Bradley, Sailing on the Thames

Lightspeed ◽  
2019 ◽  
pp. 49-57
Author(s):  
John C. H. Spence
Keyword(s):  
Eighteenth Century ◽  
Experimental Evidence ◽  
The Sun ◽  
Theory Of Relativity ◽  
Speed Of Light ◽  
Astronomical Observations ◽  
The Earth ◽  
Independent Estimate ◽  
The Universe ◽  
At Home

The story of the astronomical observations of James Bradley in the eighteenth century, whose measurements of the small movements of a star throughout the year provided an independent estimate of the speed of the Earth around the Sun relative to the speed of light. His work provided the first experimental evidence in support of Copernicus’s theory that the earth is in motion, and against the idea that it is stationary at the center of the universe. His simple telescope at home, his brilliant idea and perseverance, and his life’s work and influence. The importance of his result for the development of Einstein’s theory of relativity and for theories of the Aether in the following centuries.

scholarly journals Methods to Test the “Dimming Effect” Produced by a Decrease in the Number of Photons Received from Receding Light Sources

2021 ◽  
Author(s):  
Mark Zilberman ◽  
Keyword(s):  
Light Source ◽  
Opposite Direction ◽  
Cosmological Models ◽  
Light Sources ◽  
The Sun ◽  
Relative Speed ◽  
Speed Of Light ◽  
Relativistic Systems ◽  
The Earth

The hypothetical “Dimming effect” describes the change of the number of photons arriving from a receding light source per unit of time. In non-relativistic systems,the "Dimming effect" occurs due to the fact that as light sources move away, the distance between the emitter and the receiver constantly increases, and the photons always take longer to reach the receiver. This reduces the number of photons received per time unit compared to the number of emitted photons per time unit. Negligible for speeds incomparable with the speed of light c, the "Dimming effect" can be very significant for speeds above 0.1c. “Dimming effect” can possibly be tested in a physics labor-atory using a moving light source (or mirror) and photon counters located in the travel direction and in opposite direction. It can possibly also be tested utilizing the orbital movement of the Earth around the Sun. If confirmed, “Dimming effect” would allow astronomers to adjust values of the "Standard Candles", which are critical in cosmological models. Absence of “Dimming effect” will mean that the number of photons arriving per time unit does not depend on the relative speed of light source and observer,which is not so apparent

scholarly journals LIMITS ON CHARGE NON-CONSERVATION FROM POSSIBLE SEASONAL VARIATIONS OF THE SOLAR NEUTRINO EXPERIMENTS

2004 ◽  
Vol 19 (08) ◽  
pp. 639-644 ◽  
Author(s):  
MANUEL TORRES ◽  
HECTOR VUCETICH
Keyword(s):  
Equivalence Principle ◽  
Dimensionless Parameter ◽  
Weak Decay ◽  
The Sun ◽  
Variable Speed ◽  
Speed Of Light ◽  
Upper Limit ◽  
The Earth ◽  
Neutrino Experiments ◽  
Einstein's Equivalence Principle

Variable speed of light (VSL) theories may lead to large violations of charge conservation that can be written in terms of a dimensionless parameter λ. Similarly, charge non-conservation can arise in theories that break down Einstein's Equivalence Principle, parametrized in terms of Γ0. It is shown that for such theories, the motion of the Earth with respect to the Sun would produce a seasonal variation for the SAGE and GALLEX–GNO experiments. Analyzing the reported counting rates for these experiments, a very stringent bound |λ|≤2×10-19 is obtained, some 109 times smaller than previous ones. For the second example, the corresponding bound is |Γ0|<10-18, which represents an improvement of 107 on the previous result. Furthermore, assuming that the previous conditions apply, the existing bound for the lifetime of the 71 Ga →71 Ge charge-nonconserving decay is improved as: τ CNC ≥1.4×1027 years. Similarly a new upper limit for the ratio of the charge-nonconserving to the normal weak decay of the neutron is obtained: [Formula: see text].

Seti Space Missions

1997 ◽  
Vol 161 ◽  
pp. 761-776 ◽  
Author(s):  
Claudio Maccone
Keyword(s):  
Electromagnetic Waves ◽  
Space Missions ◽  
Gravitational Lens ◽  
The Sun ◽  
Space Antenna ◽  
Focal Distance ◽  
Large Space ◽  
The Earth ◽  
Space Antennas ◽  
New Space

AbstractSETI from space is currently envisaged in three ways: i) by large space antennas orbiting the Earth that could be used for both VLBI and SETI (VSOP and RadioAstron missions), ii) by a radiotelescope inside the Saha far side Moon crater and an Earth-link antenna on the Mare Smythii near side plain. Such SETIMOON mission would require no astronaut work since a Tether, deployed in Moon orbit until the two antennas landed softly, would also be the cable connecting them. Alternatively, a data relay satellite orbiting the Earth-Moon Lagrangian pointL2would avoid the Earthlink antenna, iii) by a large space antenna put at the foci of the Sun gravitational lens: 1) for electromagnetic waves, the minimal focal distance is 550 Astronomical Units (AU) or 14 times beyond Pluto. One could use the huge radio magnifications of sources aligned to the Sun and spacecraft; 2) for gravitational waves and neutrinos, the focus lies between 22.45 and 29.59 AU (Uranus and Neptune orbits), with a flight time of less than 30 years. Two new space missions, of SETI interest if ET’s use neutrinos for communications, are proposed.

Spots on the Sun and Life on the Earth

2019 ◽  
Vol 15 (1) ◽  
pp. 73-77
Author(s):  
Valentina V. Ukraintseva ◽  
Keyword(s):  
The Sun ◽  
The Earth

Much Ado about (Practically) Nothing

2010 ◽  
Author(s):  
David Fisher
Keyword(s):  
Energy Source ◽  
Atomic Nucleus ◽  
The Sun ◽  
Scientific Journals ◽  
Rare Gases ◽  
Important Work ◽  
The Earth ◽  
Wide Range ◽  
Life On Mars ◽  
The Universe

There are eight columns in the Periodic Table. The eighth column is comprised of the rare gases, so-called because they are the rarest elements on earth. They are also called the inert or noble gases because, like nobility, they do no work. They are colorless, odorless, invisible gases which do not react with anything, and were thought to be unimportant until the early 1960s. Starting in that era, David Fisher has spent roughly fifty years doing research on these gases, publishing nearly a hundred papers in the scientific journals, applying them to problems in geophysics and cosmochemistry, and learning how other scientists have utilized them to change our ideas about the universe, the sun, and our own planet. Much Ado about (Practically) Nothing will cover this spectrum of ideas, interspersed with the author's own work which will serve to introduce each gas and the important work others have done with them. The rare gases have participated in a wide range of scientific advances-even revolutions-but no book has ever recorded the entire story. Fisher will range from the intricacies of the atomic nucleus and the tiniest of elementary particles, the neutrino, to the energy source of the stars; from the age of the earth to its future energies; from life on Mars to cancer here on earth. A whole panoply that has never before been told as an entity.

Dombey and Son

2008 ◽  
Author(s):  
Charles Dickens ◽  
Dennis Walder
Keyword(s):  
Family Relationships ◽  
The Sun ◽  
The Novel ◽  
The Earth ◽  
The Future ◽  
Original Illustrations ◽  
The One

Dombey and Son ... Those three words conveyed the one idea of Mr. Dombey's life. The earth was made for Dombey and Son to trade in, and the sun and moon were made to give them light.' The hopes of Mr Dombey for the future of his shipping firm are centred on his delicate son Paul, and Florence, his devoted daughter, is unloved and neglected. When the firm faces ruin, and Dombey's second marriage ends in disaster, only Florence has the strength and humanity to save her father from desolate solitude. This new edition contains Dickens's prefaces, his working plans, and all the original illustrations by ‘Phiz’. The text is that of the definitive Clarendon edition. It has been supplemented by a wide-ranging Introduction, highlighting Dickens's engagement with his times, and the touching exploration of family relationships which give the novel added depth and relevance.

scholarly journals III. On the nature and construction of the sun and fixed stars

1795 ◽  
Vol 85 ◽  
pp. 46-72 ◽  
Keyword(s):  
Central Body ◽  
Planetary System ◽  
Considerable Progress ◽  
The Sun ◽  
Great Satisfaction ◽  
The Earth ◽  
The World ◽  
Celestial Bodies ◽  
The Universe ◽  
Made In

Among the celestial bodies the sun is certainly the first which should attract our notice. It is a fountain of light that illuminates the world! it is the cause of that heat which main­tains the productive power of nature, and makes the earth a fit habitation for man! it is the central body of the planetary system; and what renders a knowledge of its nature still more interesting to us is, that the numberless stars which compose the universe, appear, by the strictest analogy, to be similar bodies. Their innate light is so intense, that it reaches the eye of the observer from the remotest regions of space, and forcibly claims his notice. Now, if we are convinced that an inquiry into the nature and properties of the sun is highly worthy of our notice, we may also with great satisfaction reflect on the considerable progress that has already been made in our knowledge of this eminent body. It would require a long detail to enumerate all the various discoveries which have been made on this subject; I shall, therefore, content myself with giving only the most capital of them.

scholarly journals A review of the SCOSTEP’s 5-year scientific program VarSITI—Variability of the Sun and Its Terrestrial Impact

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Kazuo Shiokawa ◽  
Katya Georgieva
Keyword(s):  
Solar Wind ◽  
Interplanetary Space ◽  
Solar Wind Plasma ◽  
The Sun ◽  
Scientific Program ◽  
Solar Cycles ◽  
Grand Minimum ◽  
The Earth ◽  
Earth Connection ◽  
Near Future

AbstractThe Sun is a variable active-dynamo star, emitting radiation in all wavelengths and solar-wind plasma to the interplanetary space. The Earth is immersed in this radiation and solar wind, showing various responses in geospace and atmosphere. This Sun–Earth connection variates in time scales from milli-seconds to millennia and beyond. The solar activity, which has a ~11-year periodicity, is gradually declining in recent three solar cycles, suggesting a possibility of a grand minimum in near future. VarSITI—variability of the Sun and its terrestrial impact—was the 5-year program of the scientific committee on solar-terrestrial physics (SCOSTEP) in 2014–2018, focusing on this variability of the Sun and its consequences on the Earth. This paper reviews some background of SCOSTEP and its past programs, achievements of the 5-year VarSITI program, and remaining outstanding questions after VarSITI.

scholarly journals XXIV. A discourse concerning the menstrual parallax, arising from the mutual gravitation of the Earth and Moon; it's influence on the observations of the Sun and Planets; with a method of observing it: By J. Smeaton, F. R. S

1768 ◽  
Vol 58 ◽  
pp. 156-169 ◽  
Keyword(s):  
Center Of Gravity ◽  
The Sun ◽  
Sir Isaac Newton ◽  
Isaac Newton ◽  
The Earth ◽  
Common Center

It is demonstrated by Sir Isaac Newton in the Principia , that it is not the Earth's center, but the common center of gravity of the Earth and Moon, that describes the ecliptic; and that the Earth and Moon revolve in similar ellipses, about their common center of gravity.

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