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The Eerie Silence by Paul Davies

Radio astronomy began after WWII, when the developmet of radar vastly improved the power and fidelity of radio receivers. Cheap wartime equipment formed the basis of the first radio telescopes

19 September 1959: Seti Day One. Cornell paper

April 1960: Frank Drake begins Project Ozma Secret military radar establishmet

To date SETI surveys have covered only a few thousand stars within 100 light years of the Sun

Assumption: aliens will want to contact us, and will use the simplest and most easily decodable forms of transmission

Assumption: Aliens would employ a transmission method that was transparent to our atmosphere

The hydrogen line (multiplied by pi?)

Modern SETI searchers don't try to second-guess aliens' intentions; they monitor millions or billions of channels

Optical SETI: searching for faint, high-energy pulses of light

Laser communication came only a cetury after radio: why would a civilization thousands of years beyond us use it?

We tend to craft our aliens in light of our current politics (cold war, environmentalism). What will they be in 100 years?

ETI is predicted by current scientific theories; unlike ghosts or telepathy

2002: SUNY Stony Brook: Polio virus assembled from scratch

A message not meant for us, but sent thousands of years ago and crossign our line of sight (not likely)

Catching onto the galactic news network (requires massively powerful transmitters)

eavesdropping on radio communications (50-400 MHz as opposed to 1-2 GHrz for current SETI

LOFAR: Low Frequency Array

Future Square Kilometer array

These would be unlikely to find radio or TV signals, unless they were continuously monitored for a month, and filterd to remove any terrestrial signals on the same waveband

We have moved on to fiber optics; in 100 years our planet could be radio silent

Percolation theory: Geoffrey Landis

Assumption: Travel between stars is difficult and expesive

Assumption 2: cetralised cultural cotrol is impossible; a patchwork of local cultures is more likely

Some cultures will expand, others will consolidate

Assumption 3: Conquest is exceedingly ulikely

ultimately the more zealous and the less zealous fill the galaxy, and gaps of unoccupied territory still remain

Robi Haso: competition

ChangeMe123

Evidence for galactic civilization: statistically improbable reduction of materials in certain regions (suggesting harvesting) absence of magnetic monopoles: universal or local (alien energy source)

1964: Nikolai Kardashev employed a metric based on energy consumption (Soviet bias? Information today?)

Type I: All the energy of its home planet Type II: All the energy of its star (Dyson sphere, rotating black hole) Type III: All the energy in a galaxy

Mention Percy, Nik

Project cyclops ames research center- still a SETI hotbed today.

NASA established a SETI center at Ames in 1976; JPL established an office in 1977

1982: Sagan SETI petition, published in the letters page of Science

1990: SETI becomes an approved NASA project - 200 million dollars ebtween 1990 and 2001 October 1992: High Resolution Microwave Survey (HRMS) 1984: SETI Institute founded Jill Tarter: first scientist to dedicate her career to SETI. Project Phoenix: 1995-2004 META, Project Sentinel, SERENDIP
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Le Verrier
Herschel lived for one Uranian year

Bode located Uranus in a small number of earlier star catalogs, including Tobias Meyer in 1756 and John Flamsteed in 1690

Uranus refused to behave- in the early 1800s, it moved to slowly, after 1822, it moved to quickly. Precovery images made the problem worse- ephemerides could be computed either for the older orbits or the new, but not both. Even throwing out the old observations didn't work; the planet remained off course.

Alexander Fixlmillner of Kremsmunster Observatory in austria derived an ephemeris based on every known observation of Uranus published by bode in 1786

by 1788, Fixlmillner's ephemeris failed to accord with observations, unless Flamsteed's observation in 1690 were excluded.

In 1790 Jean Baptiste Joseph delambre calculated a new ephemeris for the orbit of Uranus that took into account the gravitational effects of Jupiter and Saturn. With those in place, the issue appeared to have been resolved. For this he was awarded a prize by the French academy of sciences.

By 1800, however, Uranus began acting out again.

Alexis Bouvard, an assistant ("computer") of Leplace, a methematical prodigy and onetime shepherd boy,  was arguably the first person to suggest an undiscovered planet ( planète troublante) may be disturbing Uranus's orbit. Though he did so in a fairly backhanded manner. Deciding that all pre-1781 observations of the planet were not to be trusted, he instead based his tables purely on post-1781 observations only. "It is in the exactness of the ancient observations where the doubt falls" but "I leave to the future the task of discovering whether the difficulty of reconciling the two systems results from the inaccuracy of the ancient observations, or whether it depends on some extraneous and unknown influence which may have acted on the planet."

over the following decades, the error in Bouvard's tables kept increasing; 12 arcseconds, 23 arcseconds, 30 arcseconds

Explanations for Uranus's peculiar orbit included that it was hit by a comet (whcih would explain its sudden shift in orbit but not its continuing shifts since then, unless it was being hit repeatedly) a slowing interplanetary medium (which apparently only affected uranus itself) or a giant invisible moon (which would have to have been as large as Uranus)

George Biddel Airy was, despite his name, a very unimaginative man who believed the GRO should stick to its remits of aiding navigation and plotting the moon's motions, not searching for new planets. Despite being queried several times on the possibility that an unknown planet was tugging at Uranus, he refused to countenance the idea.

Airy was spectacularly, obsessively, unnervingly boring. He would note the date on his stained blotting paper, mark empty boxes as "empty", force his staff to remain at their posts even on cloudy days (and ensure they were personally) and did not throw away a single scrap of paper he wrote on.

He declared Charles Babbage's computer "worthless" in 1842 and had it melted down for scrap.

Freidrich Willhelm Bessel was an early convert to the idea that an undiscovered planet may be behind the irregularities, and began to spread the word in 1840

In 1841, John Couch Adams, a mathematical prodigy from Cornwall, set himself the task of determining if a planet were causing the observed purterbations. This was harder than it seems- workign out the gravitational effects of a planet you know exists is easy; locating a planet purely by gravitational purterbations, on the other hand, is so difficult earlier mathematicians might well have balked at it.

His examiners at cambridge noticed that, while taking the Mathematical Tripos, the daunting cambridge maths exam, he would stare at the questions without writing anything and then, having worked out the answers in his head, wrote out the answers quickly.

By 1845, he had determined an orbit for a planet that was within 1.5 degrees of Neptune's then-current location, and handed the results to the head of the Cambridge Obseratory, James Challis, who, disquieted by the thought of doing something completely novel in scientific history (searching for an object based solely on gravitational theory) handed the tables to Airy.

But Adams was not a showman- subseuent historians have suggested he may have had an autistic spectrum disorder like Aspergers Syndrome- and his half-hearted attempts to inform his superior, Sir George Airy, in particular his failure to answer him concerning the radius vector problem- ie whether or not his calculations accounted for purtubations in both longitude and distance from the Sun- ultimately cost Britain Neptune. Why Adams refused to answer this question that Airy considered non-negotiable is uncertain. Some suggest he may have considered it trivial.

he calculated the values of mathematical constants to 200 decimal places for fun.

When Airy learned of Le Verrier's search, he pressured Challis to find it himself. Adams continued to refine his work, but continuously came up with different positions.

Challis may have seen Neptune on July 30 and August 12, but did not recognise it

At least, that's the official story. The truth has more to do with politics than science- Britain and france didn't like each other very much at the time, and the spun story was a conveinient way to get joint British credit for the discovery. In fact Adams's predicted positions for Neptune ranged across 20° of the zodiac, which led British astronomers on a six-week wild goose chase while Le Verrier's calculations allowed astronomers to locate Neptune in half an hour. The RGO's files on Neptune were kept quiet, until the file just.. vanished. Olin J Eggan, chief assistant to the Astronomer Royal Richard Woolley, had long been suspected of having stolen it. But it wasn't until his death in Chile in 1999 that the files were relocated and showed once and for all that Le Verrier deserved the lions share of the credit.

Olin Jeuck Eggen: a staff astronomer at the inter-American observatory in Chile

"borrowed" the Greenwich observatory's Neptune file while composing short biographies of Challis and Airy. Never returned it. Found after his death. He left after a row and went around the world, first to California, then to Australia, and then to Chile. When asked directly if he had the Neptune files, he denied it.

Adams was never closer than 4 degrees. People who asked to see the Neptune File before it disappeared were refused. mass vs distance perturbation

10 thosand written pages of calculations

"Discovered a planet "with the tip of a pen, without any of his instruments other than the strength of calculation alone" Francois Arago

Le Verrier had also not received the blessings of his national observatory

Le Verrier wrote directly to Johan godfried Galle, bypassing Encke.

"mauvais coucheur", a bad bedfellow

"I do not know whether M. Le Verrier is actually the most detestable man in France, but I am quite certain that he is the most detested".

He noted that were the planet too far away (3x Uranus), it would have to be so massive to perturb Uranus that it would be perturbing Saturn as well.

Leverrier gathered data from Airy at Greenwich and Arago, and also used Beauvard's tables, which he found contained a number of outright errors

War with france?

"The star is not on the map!"

Began his career as a tobacco chemist, publsihing papers on match chemistry.

Despite having little astronomical training, he applied for, and got, an astronomical tutoring job after a chemist job he had applied for was filled.

Pierre Simone Laplace, the grand master of celestial mechanics, had died in 1827. There was no one of the same caliber who could replace him. Leverrier, "who hardly had any sense of his own limitations" was to try.

Within two years he had mastered celestial mechanics to the point where he submitted paper on the subject

enke, the noblest triumph of theory that I know

Leverrier proposed the name neptune for the planet, which was accepted within a month.

Arago suggested leverrrier search for a perturbing planet on 1 September 1845; the planet was discovered on 24 September 1846.

le verrier initially wanted to call teh object neptuen, but settled on Le verrier instead. and began calling Uranus Herschel. Arago promoted the idea, and lionised le verrier in public, for "hideous circumstances" -delaunay blackmail letter French minister of information - "not appropriate here to lift the veil", some argued due to Leverrier discovering an affair between his wife and arago.

When Airy demanded an account of the radius vector, Le Verrier had no qualms about answering him- Bouvard's tables were wrong and indeed, "It is in fact one of the consideratins that must increase the likelihood of the truth of my results, that they scrupulously account for all aspects of the problem".

according to his acquaintance, joseph bertrand:

Severe in the demands he placed upon himself, he was no less so in those he placed upon others. for this reason perhaps, or perhaps for no reason at all, he had littel intercourse with the other astronomers. In condequence, he had few friends among them, and the brilliance of his successes did not make any difference. Through many controversies, the admiration with which he was first regarded did not last, nor did it produce any sustained good will toward him

"the envy, the sloth, the ignorance, the greed and other capital sins he encountered among his astronomical colleagues."

After being appointed head of the Paris Observatory in 1854, he coninued to make enemies, particularly Camille Flammarion, who would become a journalist and excoriate him in the media: firing people at random, even against the wishes of government; denying those he disliked access to assistants and even coal in winter. Eventually a committee formed that reccommended he be fired from his position.

Airy was not happy with Le Verrier's name of Neptune for the planet, and suggested Oceanus (son of Uranus) but Le Verrier preferred Neptune

John Herschel fought the idea of renaming Neptune Le Verrier, arguing that he didn't want Uranus to have his father's name.

Sir John Herschel decided to make Adams's work public, and published them in teh London paper, the Anthenaeum.

Mr. Herschel as communicated to me, which is in very bad taste, and fails to do me justice. 27 …. What can be his motive? I can’t quite understand him, especially when he descends to insinuations which I fi nd mortifying. Of what use, therefore, is it for Mr. Herschel to cry out, before all England, that I was not good enough to deserve his con fi dence?… Have I been so wrong in the theory of the secular inequalities? Is the theory of Mercury so far in error…? … But the story is perfectly clear given that not a single line of serious work had been published [by anyone else] in the course of all my researches. And only now Mr. Herschel belatedly comes around to raise a claim in favor of historical documents!

Why, the day after the discovery of my planet, does he not see that he brought into question his scienti fi c judgment, by placing under an injurious suspicion a labor which in fact had been con fi rmed in the most spectacular manner?

Teh one person who seemed to care not a jot about the events was Adams, who saw it mainly as a chance to do some more caculations. when he met Le Verrier in 1847, he immediately began speaking to him like an old friend.

Rather than award the Royal Astronomical Society's gold medal, John Herschel awarded both Adams and Le Verrier special "testamonials".

Adams eventually succeeded challis as head of the Cambridge Observatory, and won his second Copley medal for determining the extent of the Moon's retreat from the Earth. He eventualyl succeeded Airy as Astronomer Royal and played an important role in promoting women's education at Cambridge.

Vulcan
November 8 1915: Berlin: Einstein announces his general theory of relativity

the theory took eight years- special relativity was published in 1905

In 1839, Le Verrier published calculations of the orbits of the four inner planets, and showed that their mutual gravitational influences mean that their future positions are, in the long term, unpredictable. A transit of Mercury in 1845 was 16 seconds behind Le Verrier's prediction. It meant that Le Verrier had missed something affecting Mercury.

Charles Daverdoing, the artist who painted Le Verrier's post-Neptune portrait, attempted to downplay his behaviour at the Observatory, saying he "A good natured fellow, very cheerful and good company... He did not make allowences for the age or stamina of his workers... he was never one to bite his tongue, and more than once laid his hands on someone".

Le Verrier wanted to construct the most accurate vision of the solar System ever seen, and to that end had corralled his assistants into an assembly line of tabulation after tabulation, determined to get the distances and masses right to the highest possible precision.

To Le Verrier, after the triumph of Neptune, altering the Law of gravitation would be "unallowable"

The difference was tiny, but it was there, and outside the margin of error, or by the gravitational effects of other planets

38 arcseconds per century- one extra orbit of mercury every 3.41 million years

actual figure 43 arcseconds per century, or one complete orbit every 3 million years

"A planet, or if one prefers a group of smaller planets circling within the vicinity of Mercury's orbit, would be capable of producing the anomalous perturbation."

He considered the latter option more likely, as a fully fledged planet would have been visible during a solar eclipse

He reasoned that transits of these objects may have been observed but mistaken for sunspots

In 1860, a solar eclipse in Spain offered the best present chance of spotting the asteroids.

edmond Modeste Lescarbault lived up to his name. He was a humble country doctor in a rural region of Orgres with a secret passion for astronomy. during the transit of Mercury i 1845, he came to the same conclusion as Le Verrier, that an object the size of Ceres or Pallas may lurk within Mercury's orbit. Perhaps its transits may be visible too. Such a discovery was ideal for an amateur astronomer like him. By 1859, he had assembled all the necessary tools to track such an object down.

On March 26 1859, he observed a small dot on the limb of the Sun, about a quarter the apparent diameter of mercury, and observed it to travel across the Sun's disc for 1 hour and 17 minutes,

Nine months later, after reading of Le Verrier's suspicions, he sent a letter to paris in the care of a close friend. He arrived at Lescarbault's house unnanounced

"What, with that old watch showing only minutes, dre you talk of estimating seconds?"

"one should have seen M Lescarbault" "so small, so simple, so modest and so timid"

After an hour's interrogation, Le Verrier had no remaining doubts, and congratulated the poor man on his wonderful discovery. Within a month, he had engineered his receipt of the legion d'honeur.

The name of the planet was chosen by February 1860: Vulcan.

The fact that surveys of the sun failed to turn up any Vulcan transits was easy to explian; they were working at the very limits of observation and theory, and that is hard.

Vulcan sightings were reported by amateurs and professionals around the world.

Le verrrier died on Spetember 23 1877, 41 years to the day after the discovery of Neptune. He was never a man of faith, but his faith in the existence of Vulcan was unshakeable.

One particularly notable sighting was made by in july 1878 by James Craig watson direcotr of the ann arbor observatory during a scientific expedititon to observe an eclipse in the one horse town of Separation Wyoming- a celebrity group which included thomas edison, Simon Lockyer founder of nature and discoverer of helium, and simon newcomb

but again, no one else on the expedition saw it. As the number of null sightings grew, astronomers became more and more convinced that it was a phantom