* the " hydrogen line ", aka the " 21 centimeter line ": 1420. 40575177 MHz, is used by many radio telescopes including The Big Ear in its discovery of the Wow!

The hydrogen line, 21 centimeter line or HI line refers to the electromagnetic radiation spectral line that is created by a change in the energy state of neutral hydrogen atoms.

First, by mapping redshifted 21 centimeter radiation it can, in principle, provide a very precise picture of the matter power spectrum in the period after recombination.

Second, it can provide a picture of how the universe was reionized, as neutral hydrogen which has been ionized by radiation from stars or quasars will appear as holes in the 21 centimeter background.

However, 21 centimeter experiments are very difficult.

Despite these problems, 21 centimeter observations, along with space-based gravity wave observations, are generally viewed as the next great frontier in observational cosmology, after the cosmic microwave background polarization.

The first published indications of this idea are to be found at the end of his paper on the absorption of gases already mentioned, which was read on 21 October 1803, though not published until 1805.

In 2007, Khatri and Wandelt of the University of Illinois at Urbana-Champaign realized that the 21 cm hyperfine transition in neutral hydrogen of the early Universe leaves a unique absorption line imprint in the cosmic microwave background radiation.

The deal was conducted on the basis of an exchange of 21 Gaz de France shares for 22 Suez shares via the absorption of Suez by Gaz de France.

The period of his stay in Australia also marked his leadership of an extensive survey of the absorption and emission of 21 cm line radiation by neutral hydrogen which later helped to develop the realistic model of the interstellar medium.

He also carried out systematic interferometric study of 21 cm absorption towards a large number of galactic and extragalactic sources.

Besides the well-known hydrogen line at 21 cm wavelength, the spectra of extraterrestrial radio sources may contain sharp lines characteristic of other atoms, ions, and small molecules.

Certain Autocoder statements make provision for more parameters than may be contained in the operand ( columns 21 - 75 ) of a single line on the Autocoder coding sheet.

According to the CIA World Factbook, Costa Rica's GDP per capita is US $ 10, 900 ( 2009 ); however, there is a lack of maintenance and new investment in infrastructure, 21. 3 % of the people living below the poverty line and 7. 8 % ( 2009 ) unemployed.

The blue line marks the outward from 11 < sup > th </ sup > June 1773 until to 8 < sup > th </ sup > October 1773, and the red line marks the return journey 5 < sup > th </ sup > March 1774 to 21 < sup > st </ sup > October 1774.

They are detected primarily in the 21 cm line of neutral hydrogen, and typically have a lower portion of heavy elements than is normal for interstellar clouds in the Milky Way.

Shakespeare may allude to the image when Lady Macbeth says to her husband, " Look like the innocent flower, but be the serpent under't " ( 1. 5. 74-5 ).. And the Porter's speech ( 1. 3. 1 – 21 ), in particular, may allude to the trial of the Jesuit Henry Garnet in spring, 1606 ; " equivocator " ( line 8 ) may refer to Garnet's defence of " equivocation ", and " farmer " ( 4 ) to one of Garnet's aliases.

bar: 5. 0 width: 40 from: 22 / 12 / 2003 till: 21 / 03 / 2012 color: col5. 0 mark :( line, col5. 0 )

* 2008 – An EF4 tornado strikes the Oklahoma-Kansas state line, killing 21 people and injuring over 100.

21 July 2007: YENEGOA-PORT HARCOURT LINE-According to the Daily Champion ( published in Lagos ), the Nigerian states Bayelsa and Rivers are to embark on the construction of a high-speed rail line to connect Yenagoa, the Bayelsa state capital, and Port Harcourt.

* Little Germanization: " The Frankish lexicon and its phonetic influence often end above the oc / oïl line " ( Bec, 1963, 20, 21 )

21. 4 % of the population and 22. 4 % of families are below the poverty line.

With 21 seconds left in the first half, McMahon scrambled to the Patriots ' three-yard line and was stopped in-bounds.

With time running out, Bradshaw completed 2 passes to Swann for gains of 29 and 21 yards, moving the ball to the 16-yard line with 40 seconds left in the half.

On Buffalo's first play after the botched field goal attempt, Bills quarterback Jim Kelly gave Washington another chance to score by throwing an interception to Redskins safety Brad Edwards, who returned it 21 yards to the Bills 12-yard line.

Meggett returned the ensuing kickoff 21 yards to the Patriots 25-yard line.

As another example, consider a line which runs through the points ( 4, 15 ) and ( 3, 21 ).

Within 22 years, the percentage of the population living below the national poverty line decreased dramatically from 42. 21 in 1988 to 7. 75 in 2010.

The service line is 6. 40 meters ( 21 feet ) from the net.

The programs ' signals are encoded according to their rating, on line 21 of the broadcast signal's vertical blanking interval using the XDS protocol, and this is detected by the television set's V-chip.

Playing on a line with Pittsburgh Penguins superstar Mario Lemieux, he recorded a tournament-best 21 points in nine games.

* January 21 – The first DeLorean DMC-12 automobile, a stainless steel sports car with gull-wing doors, rolls off the production line in Dunmurry, Northern Ireland.

* July 21 – First Indochina War: The Geneva Conference sends French forces to the south, and Vietnamese forces to the north, of a ceasefire line, and calls for elections to decide the government for all of Vietnam by July 1956.

* 21 cm = 2. 1 dm – wavelength of the 1. 4 GHz hydrogen emission line, a hyperfine transition of the hydrogen atom

Radio telescopes can also be used to observe neutral hydrogen ( via 21 cm radiation ), including, potentially, the non-ionized matter in the early universe that later collapsed to form galaxies.

* 1944 — Hendrik van de Hulst predicts the 21 cm hyperfine line of neutral interstellar hydrogen

* 1951 — Harold I. Ewen and Edward Purcell observe the 21 cm hyperfine line of neutral interstellar hydrogen

* Article 21 allows appeals to be made to neutral vessels to help collect and care for the wounded, sick, and shipwrecked.

In a report issued by the State Department, Undersecretary of State Stuart Eizenstat noted that the United States accepted only 21, 000 refugees from Europe and did not significantly raise or even fill its restrictive quotas, accepting far fewer Jews per capita than many of the neutral European countries and fewer in absolute terms than Switzerland.

* Hendrik van de Hulst predicts the 21 cm hyperfine line of neutral interstellar hydrogen.

The pangalactic statisticians ( a neutral organization of observers ) have stated that 21 % of all cosmological manipulations are executed by cosmocrat-servants, 16 % are executed by chaos-servants and 63 % are executed by the vast uncontrollable life itself.

Konstantinovsky ( 2009 ) states that the uses of apocatastasis in Christian writings prior to the Synod of Constantinople ( 543 ) and the anathema ( 553 ) pronounced against " Origenists " and Evagrius Ponticus were neutral and referred primarily to concepts similar to the general " restoration of all things spoken " ( restitutio omnium quae locutus est Deus ) of Peter in Acts 3: 21 and not for example the universal reconciliation of all souls which had ever been.

* February 21 – First flight by a British Royal Air Force flying boat through the " Donegal Corridor ", neutral Republic of Ireland airspace between its base in Northern Ireland and the Atlantic Ocean, a concession secretly agreed by Taoiseach Éamon de Valera.

Projects to survey the Zone of Avoidance at radio wavelengths, particularly using the 21 cm spin-flip emission line of neutral atomic hydrogen ( known in astronomical parlance as HI ), have detected many galaxies that could not be detected in the infrared.

The Dwingeloo 1 galaxy was discovered in 1994 by the Dwingeloo Obscured Galaxy Survey ( DOGS ), which searched for neutral hydrogen ( HI ) radio emissions at the wavelength of 21 cm from objects in the Zone of Avoidance.

Dwingeloo 2 was first detected at radio wavelengths from the 21 cm emission line of neutral atomic hydrogen ( known to astronomers as HI ) in the course of follow-up observations after the discovery of Dwingeloo 1.

In 1944, while a student in Utrecht, he predicted the existence of the 21 cm hyperfine line of neutral interstellar hydrogen.

VIRGOHI21 was detected through radio telescope observations of its neutral hydrogen 21 cm emissions.

This cloud of neutral hydrogen ( detectable via 21 cm H-I emissions ), unlike other HVCs shows a rotational component and dark matter.

The Arecibo radio telescope is useful where others are not because of its ability to detect the emission from this neutral hydrogen, specifically the 21 cm line.

On 21 October 1904, while passing by the United Kingdom ( an ally of Japan but neutral in this war ), they nearly provoked a war in the Dogger Bank incident by firing on British fishing boats that they mistook for Japanese torpedo boats.

When the engine starts, the car pauses for 11 s-if equipped with a manual gearbox, 6 s in neutral ( with clutch engaged ) and 5 s in the 1st gear ( with clutch disengaged )-then slowly accelerates to 15 km / h in 4 s, cruises at constant speed for 8 s, brakes to a full stop in 5 s ( manual: last 3 s with clutch disengaged ), then stops for 21 s ( manual: 16 s in neutral, then 5 s in the 1st gear ).