Using powerful telescopes atop Mauna Kea, astronomers say they’ve discovered a massive “dark” galaxy that could answer some questions about how the universe works — and raise new ones.

Researchers found the newly dubbed “Dragonfly 44” galaxy last year and then observed its movements more closely this year using the W.M. Keck Observatory and the Gemini North telescope, officials said.

It’s relatively close to Earth’s Milky Way galaxy, but astronomers had missed it for decades because it’s so dim, according to a joint W.M. Keck/Gemini Observatory statement released Thursday.

After more scrutiny an international team of astronomers concluded that Dragonfly 44 is virtually “99.99 percent” made of dark matter, the release stated. The unusual galaxy is about the same size as the Milky Way, but “it has so few stars that it would quickly be ripped apart unless something was holding it together.”

“It’s got a lot of mass, but it doesn’t have a lot of stuff giving off light,” Gemini Observatory spokesman Peter Michaud said Thursday of Dragonfly 44. The nature of dark matter “is still a huge mystery. It’s one of the big mysteries in astronomy,” he said.

Scientists characterize it as an invisible force that largely remains a mystery to them — but one that they say exists because they can observe its gravitational effects across the cosmos. Dark matter, they say, causes stars and galaxies to move and spin in certain ways.

“It does what we expect it to do gravitationally,” Michaud explained Thursday.

The Dragonfly 44 findings are being published in the Astrophysical Journal, according to the release. Its discovery “has big implications for the study of dark matter,” principal investigator Pieter van Dokkum said in a statement.

The finding also raises the question of how such a mostly dark-matter galaxy is created.