Dmitri Varfolomeyev (footballer, born 1978)
Dmitri Nikolayevich Varfolomeyev( born 15 March 1978 in Leningrad) is a former Russian football player.
He is a younger brother of Sergei Varfolomeyev.
Markus Weissenberger
Markus Weissenberger( born March 8, 1975) is an Austrian former footballer who played as a midfielder.
He is a younger brother of former Austria international player Thomas Weissenberger.
Miloš Zličić
Miloš Zličić( born 29 December 1999) is a Serbian football forward.
He is a younger brother of Lazar Zličić.
Jack Lyons (cricketer)
John James" Jack or J.J." Lyons( 21 May 1863 – 21 July 1927) was an Australian cricketer who played in 14 Tests between 1887 and 1897.
Roman Smishko
Roman Smishko is a retired Ukrainian professional footballer who played as a goalkeeper.
He is a younger brother of Ukrainian defender Bohdan Smishko.
Jackie Robinson (basketball, born 1927)
Robert Lloyd Jackson Robinson( born April 26, 1927), nicknamed" Jack" or" Jackie", is a retired American Baptist pastor and theologian and was a college basketball player who competed in the 1948 Summer Olympics.
Christian Eichner
Christian Eichner( born 24 November 1982) is a German retired football defender.
Anton Shunto
Anton Shunto( born 31 May 1988) is a Belarusian professional footballer.
As of 2019, he plays for Molodechno.
He is a younger brother of Denis Shunto, who is a founder and former president of Krumkachy Minsk.
William Brydone Jack
William Brydone Jack, (23 November 1817 – 23 November 1886), was the University of New Brunswick's first surveying professor and its second president (1861-1885).
He was educated at the University of St Andrews, Scotland.
In 1840, he was appointed Professor of Mathematics and Natural Philosophy at what was then King's College (founded in 1785) and gave lectures in surveying as part of the mathematics curriculum.
William Brydone Jack also designed a small wooden observatory which became operational in 1851.
In 1855, William Brydone Jack, together with Dr. J.B. Toldervy, determined the longitude of Fredericton using the exchange of telegraph signals with Harvard College Observatory.
This was the first precisely determined longitude in Canada.
In 1859, the same year that the University of New Brunswick was created, a special three-term undergraduate course in civil engineering and surveying was initiated.
The first diploma in this special course was awarded to Henry George Clopper Ketchum in June 1862.
William Brydone Jack was appointed to the Board of Examiners in 1874 for the examination of candidates for admission to practice land surveying in New Brunswick.
J.E. Kennedy, professor of physics at UNB from 1945 to 1956, wrote extensively on William Brydone Jack's accomplishments in astronomy and land surveying including his efforts to build the observatory and the determination of longitude by electric telegraph.
Vadim Vlasov
Vadim Nikolayevich Vlasov( born 19 December 1980) is a former Russian football player.
He is a younger brother of Dmitri Vlasov.

Question: Who is younger, William Brydone Jack or Christian Eichner?
Answer: Christian Eichner