Gamma ray marathon bolsters Einstein’s theory of relativity

Posted Dec. 01, 2009, at 6:27 p.m.

The race might seem like a virtual tie, bursts of gamma rays of different energies and wavelengths emitted simultaneously from an exploding star some 7.3 billion light-years distant, all arriving at the Fermi Gamma-Ray Space Telescope within 0.9 second of one another.

But there was a winner and that was Albert Einstein. In his 1905 theory of relativity, Einstein said that the speed of electromagnetic radiation was constant and independent of its energy, wavelength or direction.

This is the most exacting test yet of Einstein’s statement and, as one of the principal investigators said, “Einstein is still right.” This is considered a major step in either verifying or refuting Einstein’s hypothesis.

The result will have a major effect of efforts to unify Einstein’s theory of gravity with another he never really liked, the quantum theory that governs the infinitesimally small distances within the atom.

Focus on the planets

Mercury appears above the southwestern horizon about a half-hour after sunset by midmonth. On Dec. 18, the thin crescent moon stands to the upper left of Mercury. By month’s end, the elusive innermost planet will have faded from view.

Venus rises just before the sun and is lost in the sun’s glare during December.

Mars is on track for its best appearance in two years. It rises at 10 p.m. as December opens and by 8 p.m. as the month closes. Mars continues to brighten and is prominent among the stars of Leo the Lion. Mars is tilted toward Earth, possibly affording a view of the north polar ice cap.

Jupiter is high in the southwest at dusk and is still the brightest point of light in the night sky. Jupiter’s four moons continue their dance about the planet, occasionally eclipsing or occulting one another.

Saturn is high in the south shortly before dawn. On Dec. 10, Saturn stands due north of a waning crescent moon. Its rings are providing an ever-increasing panorama as they continue to widen. The edge-on ring phenomena seen these past months will not happen again until 2025.

Uranus is high in the south-southwest at nightfall, where its blue-green disk is easily spotted with binoculars. Look for Uranus due south of the Circlet of Pisces.

Neptune spends most of December within the same field of view, i.e., about a single moon-width, of Jupiter. A telescope will pick out the tiny blue-gray disk.

December events

2 Full moon, 2:31 a.m. The full moon of December is known variously as the Cold Moon, Long Night Moon, Wolf Moon, or the Moon Before Yule.

4 The moon is at perigee, or nearest approach to Earth.

6 Look east about 10 p.m. to see the waning gibbous moon to the lower right.

9 Moon in last quarter, 7:15 p.m.

14 This is the peak night for the Geminid meteor shower, with viewing very favorable as the new moon is only two days away. The shower radiates from the vicinity of Castor in Gemini and may deliver up to 100 bright, slower meteors per hour.

16 New moon, 7:02 a.m.

18 The sun enters Sagittarius on the ecliptic.

20 The moon is at apogee, or farthest distance from Earth. Look to the southwest shortly after dark, where the moon is to the lower right of Jupiter. Very near Jupiter, and distinguishable by telescope, is Neptune.

21 Winter solstice, 12:47 a.m. The sun has traveled to its southernmost point, giving the shortest day and longest night in the Northern Hemisphere. The sun enters the astrological sign of Capricornus on the solstice, however, astronomically, is still in Sagittarius.

22 This is the peak night for the Ursid meteor shower that typically produces about 10 faint meteors per hour.

24 Moon in first quarter, 12:35 a.m.

25 Merry Christmas!

31 Full moon, 2:13 p.m. This being the second full moon of December, it is known as a blue moon. Sunrise, 7:13 a.m.; sunset, 4:04 p.m.


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