Ole Christensen Rømer (] ; 25 September 1644 – 19 September 1710) was a Danish astronomer who in 1676 made the first quantitative measurements of the speed of light.
In mathematics, more specifically in group theory, the character of a group representation is a function on the group that associates to each group element the trace of the corresponding matrix.
 The character carries the essential information about the representation in a more condensed form.
 Georg Frobenius initially developed representation theory of finite groups entirely based on the characters, and without any explicit matrix realization of representations themselves.
 This is possible because a complex representation of a finite group is determined (up to isomorphism) by its character.
 The situation with representations over a field of positive characteristic, so-called "modular representations", is more delicate, but Richard Brauer developed a powerful theory of characters in this case as well.
 Many deep theorems on the structure of finite groups use characters of modular representations.
The Heliocentric Julian Date (HJD) is the Julian Date (JD) corrected for differences in the Earth's position with respect to the Sun.
 When timing events that occur beyond the Solar System, due to the finite speed of light, the time the event is observed depends on the changing position of the observer in the Solar System.
 Before multiple observations can be combined, they must be reduced to a common, fixed, reference location.
 This correction also depends on the direction to the object or event being timed.
Syrian nationality law is the law governing the acquisition, transmission and loss of Syrian citizenship.
 Syrian citizenship is the status of being a citizen of the Republic of Syria and it can be obtained by birth or naturalisation.
 The Syrian nationality is transmitted by paternity (father) (see Jus sanguinis).
 Therefore, Syrian nationality is determined solely by the father's nationality, while the place of birth is irrelevant.
 In other words, birthright citizenship is not recognized since being born in Syria does not grant an automatic right to become a national.
 In most cases, individuals are deemed to be Syrian nationals regardless of whether they are born inside or outside Syria as long as their father holds Syrian nationality.
Rømer's determination of the speed of light was the demonstration in 1676 that light has a finite speed, and so does not travel instantaneously.
 The discovery is usually attributed to Danish astronomer Ole Rømer (1644–1710), who was working at the Royal Observatory in Paris at the time.
The invariant speed or observer invariant speed is a speed which is measured to be the same in all reference frames by all observers.
 The invariance of the speed of light is one of the postulates of special relativity, and the terms "speed of light" and "invariant speed" are often considered synonymous.
 In non-relativistic classical mechanics, or Newtonian mechanics, finite invariant speed does not exist (the only invariant speed predicted by Newtonian mechanics is infinity).
In mathematics, a simple group is a nontrivial group whose only normal subgroups are the trivial group and the group itself.
 A group that is not simple can be broken into two smaller groups, a normal subgroup and the quotient group, and the process can be repeated.
 If the group is finite, then eventually one arrives at uniquely determined simple groups by the Jordan–Hölder theorem.
 The complete classification of finite simple groups, completed in 2008, is a major milestone in the history of mathematics.
In the GSM cellular mobile phone standard, timing advance value corresponds to the length of time a signal takes to reach the base station from a mobile phone.
 GSM uses TDMA technology in the radio interface to share a single frequency between several users, assigning sequential timeslots to the individual users sharing a frequency.
 Each user transmits periodically for less than one-eighth of the time within one of the eight timeslots.
 Since the users are at various distances from the base station and radio waves travel at the finite speed of light, the precise arrival-time within the slot can be used by the base station to determine the distance to the mobile phone.
 The time at which the phone is allowed to transmit a burst of traffic within a timeslot must be adjusted accordingly to prevent collisions with adjacent users.
 Timing Advance (TA) is the variable controlling this adjustment.
Temporal resolution (TR) refers to the precision of a measurement with respect to time.
 Often there is a trade-off between the temporal resolution of a measurement and its spatial resolution, due to Heisenberg's uncertainty principle.
 In some contexts such as particle physics, this trade-off can be attributed to the finite speed of light and the fact that it takes a certain period of time for the photons carrying information to reach the observer.
 In this time, the system might have undergone changes itself.
 Thus, the longer the light has to travel, the lower the temporal resolution.
The Barycentric Julian Date (BJD) is the Julian Date (JD) corrected for differences in the Earth's position with respect to the barycentre of the Solar System.
 Due to the finite speed of light, the time an astronomical event is observed depends on the changing position of the observer in the Solar System.
 Before multiple observations can be combined, they must be reduced to a common, fixed, reference location.
 This correction also depends on the direction to the object or event being timed.

Question: What nationality was the man who determined that light has a finite speed?
Answer: Danish