Experiment with GALACTICA

Ernest Davis
November 15, 2022

First query

wiki article on experiment to determine gravitational constant

Galactica Output

Experiment to determine gravitational constant

Experiment to determine gravitational constant (GP-B) was a NASA space experiment designed to test two predictions of Albert Einstein's general theory of relativity, specifically the geodetic effect and frame-dragging.

Not to be confused with Gravity Probe B, a similar but independent experiment.The Gravity Probe B spacecraft in orbit around the Earth

Contents

History

In 1960, Leonard Schiff, then a graduate student at Princeton University, proposed an experiment to test a prediction of general relativity. Schiff suggested that the precession of a gyroscope could be measured to test the theory. He presented his idea to Robert Dicke, then at Princeton, and suggested that it could be done in space to eliminate the effect of the gravity gradient from the Earth. In 1962, Schiff received a Ph.D. in Physics and went on to become a professor at the University of Maryland. He continued to work on experimental tests of general relativity.

In 1964, Schiff received a letter from William Fairbank of Stanford University, suggesting that the gyroscope experiment could be done using the gyroscopes of the NASA Gravity Probe A mission. In 1965, Schiff and Fairbank submitted a proposal to NASA to perform the gyroscope experiment on Gravity Probe A. However, in 1966, the project was cancelled by NASA, due to budget cuts.

Schiff's student Francis Everitt then began work on the gyroscope experiment, and continued to work on it after Schiff moved to the University of Maryland. In 1967, Everitt received a Ph.D. in Physics, and joined the faculty of the University of California, San Diego (UCSD). He continued to work on the gyroscope experiment, and received a letter from NASA in 1974, asking him to propose a new experiment, based on the same principles, to be performed on a new spacecraft. The

What Galactica got right

1. Gravity Probe B was indeed a NASA satellite-based experiment to test the geodetic effect and the frame-dragging effect predicted by general relativity. Leonard Schiff was indeed the physicist who proposed the experiment and Francis Everitt was the PI on the project. William M Fairbank was a physicist at Stanford; whether he was ever involved in proposing gravity experiments, I can't tell.

2. Gravity Probe A was an earlier test of Einstein's theory.

What Galactica got wrong

1. I asked about determining the gravitational constant, not testing general relativity.

2. As far as I can determine "GP-B" is identical to "Gravity Probe-B".

3. Leonard Schiff got his doctorate from M.I.T. in 1937. He taught at various times at U. Penn and Stanford, but never at U. Maryland. Francis Everitt got his doctorate from Imperial College in 1959.

4. Gravity Probe A was not canceled in 1966 due to budget cuts nor did it have anything to do with gyroscopes. It was launched in 1976 and the experiment involved masers.

Second query

wiki article on transit of venus

Galactica Output

Transit of venus

Transit of venus is the astronomical event when Venus passes directly between the Earth and the Sun. The first known recorded transit of Venus occurred in 362 BC. The last known transit of Venus was in 1882.

Transit of Venus 2004

Contents

History

Main article: Transit of Venus ยง HistoryTransit of Venus as seen from Japan, 2004The first recorded transit of Venus was in 362 BC, when the Greek astronomer Aristarchus of Samos was able to estimate the relative distances of the Sun and Moon. This was followed by many others, including in 283 BC, 187 BC, 8 June 47 BC, 1639, 1631, 1629, 1627, 1626, 1624, 1622, 1621, 1620, 1619, 1616, 1612, 1611, 1610, 1608, 1606, 1604, 1602, 1582, 1581, 1580, 1569, 1567, 1566, 1564, 1562, 1561, 1560, 1559, 1558, 1557, 1555, 1554, 1552, 1551, 1550, 1549, 1548, 1547, 1546, 1545, 154

What GALACTICA gets right

1. The definition of transit of Venus in the first sentence is right.

2. There were indeed transits of Venus in 1882 and 2004.

3. The transit of Venus was used to compute the distance to the sun, but not until 1761.

4. Aristarchus did estimate the distance to the Sun, though not using the transit of Venus.

What GALACTICA got wrong

1. No observations of the transit of Venus were made, or could have been made, before the invention of the telescope.

2. There are only two transits of Venus in a century; they are eight years apart. So the long list of dates is gibberish.

3. The last known transit of Venus was not in 1882; there were transits in 2004 and 2012.