This question is a longstanding one in both traditional philosophy and quantum physics.
The necessity for something to be observed before it exists entails the existence of some observer. A famous Bishop Berkeley once used this argument as proof of the existence of God, the ultimate observer.
Mathematicians talk of "discovering" a new theorem. That term implies that the theorem existed in some sense before it was discovered. This contrasts with say Otto's "invention" of the four-stroke piston engine cycle, which did not exist until he invented it. But where do the idea of the four-stroke, or the mathematics of its operating cycle, lie? Where do discovery and invention divide? We see two philosophically opposed positions embedded in the English language.
Quantum physics is stuffed with counter-intuitive weirdnesses which have been demonstrated over and over again in the laboratory. One such phenomenon is the inaccessibility of any quantum wave to direct observation; either it will remain unobserved or it will "collapse" into a localised particle. The standard interpretation of all this weirdness is known as the Copenhagen interpretation. It holds that only observations exist and nothing therefore exists until it is observed; the wave describes only what you are likely to observe when you do so. (because of this the interpretation is sometimes summarised as "shut up and calculate").
The more extreme examples of this position demand a conscious observer before anything can be said to exist, while more moderate positions suggest that "observation" includes interactions with other quanta - reducing Berkeley's God to whatever arbitrary blob of stuff has gotten in the way this time.
Recent experiments in some areas have developed a technique of partial sampling or partial detection, in which individual quanta are not fully observed but, as it were, touched for some incomplete information about them. The statistical aggregation of many such partial measurements yields firm results without collapsing the wave function. (These experiments include such joys as sending the mass of an electron down one path and its spin down another, combining them back together at the finishing line.)
While this weakens some aspects of the Copenhagen position, such as the impenetrability of the wave function, it does not affect the strong position of demanding an observer to do so.
Others of course feel that the whole observer business is a load of sophistry and there has to be some underlying reality independent of all such nonsense. Copenhagen is just a cover for our ignorance and, given time, we will learn to further invade the wave function's privacy.
So, certainly for now, the answer to the question is a matter of opinion. It may or may not become clearer as science advances.