Our galaxy is a spiral galaxy that comprises a disc of stars, dust, and gas, and its spiral arms are delimited. Initially, scientists believed that the disc was just flat. Later on, they figured out something else.
Apparently, the Milky Way’s outermost part of the disc is pretty distorted into something dubbed a “warp.” This part is also twisted upwards in one direction and downwards in the other, resembling something familiar: a spinning top? But does our galaxy move like one?
Here is what you need to know.
To Spin is a Full Complicated Process
A team of astrophysicist started questioning if the wobble in the axis of rotation of the disc warp is actually incorrect.
First discovery
Back in 2020, the finding the precession of the warp of our galaxy’s disc was announced. Scientists explained that the deformation is not static and resembles a spinning top’s movement. They also predicted a cycle of 600-700 million years, around three times it needs the Sun to move once around the centre of the Milky Way.
New study insights
Recently, scientists analyzed the variation of the amplitude of the warp with the ages of the stars.
“[…] the stars which are a few tens of millions of years old, such as the Cepheids, have a much larger warp…,” explains Zofia Chrobakova, a predoctoral researcher at the IAC.
So, it’s possible that the precession can disappear or turn into something slower. The team used data from the Gaia Mission of the ESA (the European Space Agency) to reach such insights. More research is indeed necessary to figure more things out.
Precession is quite the phenomenon. It doesn’t occur only in galaxies but on Earth, too. And its annual revolution around the Sun, as well. This is because Earth’s axis precesses the rotation period of 24 hours, meaning that the celestial pole is not close to the present pole star all the time.