What would you do if in the middle of the night, a stranger asked you to legally declare your financial support for an immigrant family that you would never meet-and hadn't even arrived in your country yet?

That was essentially the proposition that Barnet Yudin, a Russian-American Jew, faced one night in 1938 when a stranger, who was going door-to-door, appealed to the man asking if he could help a Jewish family from Germany flee to North America.

While Yudin hadn't gone on to be the doctor he dreamed of being, he and his family lived comfortably in Belleville, New Jersey-and his job as a paint salesmen brought in a healthy $120 a month.

Nevertheless he was not just being asked for a donation, but rather to sign an affidavit of support for an entire family, saying he would financially keep them afloat if required, until they could find their footing in a new country.

It required him to reveal banking information, his net worth, monthly income, and more, all in order to help the Penzias family secure immigration visas, likely sparing them from Nazi concentration camps.

All this he did, and was given the promise that the family would never contact him.

Because of Yudin's act of kindness, the Penzias family made it to the shores of North America. The older of the two sons, Arno, would go on to become the physicist that discovered the Cosmic Microwave Background-one of the strongest pieces of evidence supporting the Big Bang Theory of the universe, for which he collected the Nobel Prize.

Arno is now retired in Northern California at 89 years of age. Recently, National Geographic reported that his son David came across some family papers containing an envelope. Inside was a copy of that affidavit from Yudin, and all the personal bank documents he provided to certify it.

Shocked at the kindness this stranger had shown to his father and grandfather, David did some sleuthing and eventually came across the name of someone he was fairly certain was Yudin's relative, a New Jersey resident named Robert.

The call was a strange one, but soon, more of Yudin's descendants were involved in piecing together the remarkable story of the family patriarch.

At David's request, the two families got together at Yudin's grandson's home for bagels, lox, and whitefish. Together they exchanged documents and memories, centered round a picture of Arno Penzias surrounded by his 5 children and 10 grandchildren.

"None of these people would exist today without Barnet Yudin," David said, emphasizing the difference that Yudin's choice made.

Joe Yudin, a great-grandson, told Nat Geo that his grandfather didn't say, "Is this kid going to win the Nobel someday, or play shortstop for the Yankees? He did what he did because it was right and didn't mention it to anybody. He definitely had this big picture of what humanity should be like."

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