The Universe from the Center
Modern precision timekeeping explored By Dr. George Spagna Special to Ashland-Hanover Local
W
e have been tracing a brief history of time and timekeeping. Last month I promised a final discussion on modern precision timekeeping. Recall that the year is measured by Earth’s orbit around the Sun in about 365.25 days. The second used to be defined as a fraction of the tropical year 1900, approximately one 31.56 millionth of that year, or one 86,400th of a day. But our rotation rate is not constant – it can change with earthquakes, tides, and even human activity like building large reservoirs. That’s not a big deal for most of us, but your computers need more precision and so does science. The official time standard for the U.S. is a “cesium fountain atomic clock” in Boulder, Colorado, maintained by the National Institute of Standards and Technology (NIST). A quick search of their web site (nist.gov) finds the following history:
LAWS Continued from pg. 1
or capacity to make, communicate or carry out reasonable decisions concerning his well-being or has one or more limitations that substantially impair the adult’s ability to independently provide for his daily needs or safe guard his person, property or legal interests. It is now a class 1 misdemeanor for an agent under a power of attorney to knowingly or intentionally engage in financial exploitation of an incapacitated adult who is the principal of that agent. A person may be prosecuted for a stalking charge in the jurisdiction where such person resides at the time of the stalking. Evidence of any conduct that occurred outside of Virginia may be admissible, if relevant, in any stalking trial. Law enforcement officers may make an arrest without a warrant when in close pursuit and the arrest is made beyond the boundary of the jurisdiction from which the arrestee fled. The
2
law enforcement officer shall procure a warrant(s) from the magistrate serving the jurisdiction where the arrest was made, changing the arrestee with an offense(s) in the jurisdiction where the arrest was made, charging the arrestee with offense in the jurisdiction from where he fled and any offense(s) committed during the close pursuit where such offense(s) occurred. Those riding bicycles, electric personal mobility devices, electric powerassisted bicycles or motorized skateboards or scooters two abreast may not impede the normal and reasonable flow of traffic and shall, as quickly as practicable, move into a single file formation when being overtaken by a faster moving vehicle. Criminal investigative files relating to a criminal investigation or proceeding that is not ongoing are excluded from the mandatory disclosure provisions of the Virginia Freedom of Information Act. Exceptions are provided for attorneys representing a petitioner or inspection by an
Ashland-Hanover Local July 6, 2022
In 1945 Isidor Rabi, a physics professor at Columbia University, suggests a clock could be made from a technique he developed in the 1930s called atomic beam magnetic resonance. In 1949, using Rabi's technique, NIST (then the National Bureau of Standards) announces the world's first atomic clock using the ammonia molecule as the source of vibrations. In 1952, NIST completes the first accurate measurement of the frequency of the cesium clock resonance. The apparatus for this measurement is named NBS-1. In 1954, NBS-1 is moved to NIST's new laboratories in Boulder, Colorado. In 1955, The National Physical Laboratory in England builds the first cesium-beam clock used as a calibration source. In 1956, commercial cesium clocks become available, costing $20,000 each. In 1959, NBS-1 goes into regular service as NIST's primary frequency standard. In 1960, NBS-2 is inaugurated in Boulder; it can run for long periods unattended and is used to calibrate secondary standards. In 1963, the search for a clock with improved accuracy and stability results in NBS-3. In 1967, the attorney or a person proceeding pro se (without benefit of counsel) in a petition for a writ of habeas corpus or writ of actual innocence. No criminal investigative file shall be disclosed to any requester except the victim, immediate family members, if the victim is deceased, or the victim’s parents or guardian if the victim is a minor. If the immediate family member and/or the parent or guardian is considered a person of interest or a suspect in the investigation or proceeding, there is a provision whereby the circuit court of the jurisdiction can issue an injunction preventing disclosure. Credit for time spent in confinement while awaiting trial will now include any time spent in pretrial confinement or dentition on separate charges that are from the same act as the violation for which the person was convicted and are dismissed or not prosecuted. New legislation clarifies that if the owner of a place to be searched pursuant to a search warrant is not present,
a copy of the search warrant and affidavit shall be given to at least one adult occupant of the place to be searched. Commencing July 1, a person is guilty of a class 1 misdemeanor if he or she operates a motor vehicle in a careless or distracted manner and causes death or serious bodily injury of a vulnerable road user. The previous statute only mentioned serious bodily injury. Upon conviction, one’s privilege to operate a motor vehicle may be suspended or restricted for up to six months. Any person who knowingly (i) engages in sexual contact with an animal; (ii) causes another by force, threat or intimidation to engage in sexual contact with an animal; (iii) advertises, solicits, offers, sells, purchases or possesses an animal with the intent that the animal be subject to sexual contact; (iv) permits sexual contact with an animal to be conducted on any premises under his ownership or control; or (v) produces, distributes, publishes, sells, transmits, finances, possesses
13th General Conference on Weights and Measures defines the second on the basis of vibrations of the cesium atom; the world's timekeeping system no longer has an astronomical basis. In 1968, NBS-4, Metro Creative Connection the world's most stable cesium clock, is completed. This clock was used into the 1990s as part of the NIST time system. In 1972,NBS-5, an advanced cesium beam device, is completed and serves as the primary standard. In 1975, NBS-6 begins operation; an outgrowth of NBS-5, it is one of the world's most accurate atomic clocks, neither gaining nor losing one second in 300,000 years. In 1989, the Nobel Prize in Physics is awarded to three researchers: Norman Ramsey of Harvard University, Hans see UNIVERSE, pg. 11
or possesses with intent to distribute, publish, sell or transmit an obscene item depicting a person engaged in sexual contract with an animal is guilty of a class 6 felony (one to five years in the penitentiary or up to 12 months in jail). A law enforcement officer or animal control officer is required to apply to a magistrate for a summons for a vicious dog if such officer is in either the jurisdiction where the dog resides or where the dog committed an act set forth in the definition of vicious dog. Currently, such action is required only if the officer is in the jurisdiction where the dog resides. Any dog engaged in lawful hunting must wear a substantial collar with a tag that identifies the name of the owner or custodian of the dog and a current phone number. Willfully, breaking, tampering, injuring or removing any part of a motor vehicle, aircraft, boat, vessel or temporarily or permanently preventing its useful operation when such actions involve the breaking, injuring, tampering with or removal of a catalytic
converter or the parts thereof is a class 6 felony. This new legislation is clearly a response to the drastic increase in catalytic converter thefts. Motor vehicles, trailers and semi-trailers exempted from the registration requirement must be covered by motor vehicle insurance, a general liability policy or an umbrella or excess liability policy. An owner must provide proof of the above insurance within 30 days when requested by a law enforcement officer or be subject to a $600 fine to be paid into the Uninsured Motorist Fund. Again, I emphasize the preceding materials do not address all changes to the law or all new legislation from the past General Assembly. Any questions may be addressed by calling my direct line at (804) 365-6186. As always, my thanks to my fellow citizens for the privilege of serving as your Commonwealth’s Attorney and for your support. Submitted by R. E. “Trip” Chalkley, III, Commonwealth’s Attorney, Hanover County.
