Ask a NASA astronomer! How many galaxies are out there?

If we ever discover the true size of the universe—is it infinite or just too big to measure?—we'll likely have galaxies to thank. The trillions of massive star clusters we've observed are sending light from the early universe back to us. But our measuring instruments—the strongest of which is NASA's Hubble Space Telescope—aren't powerful enough to detect light from furthest points of the universe. But in 2020, the James Webb Telescope should be able to, revealing a truer number of galaxies and perhaps the boundaries of the universe itself.