Spiral galaxy NGC 5457 aka the Pinwheel Galaxy [image credit: European Space Agency & NASA]
No mention of electricity here, although it’s required to create the magnetism: ‘The magnetic behavior of a material depends on its structure, particularly its electron configuration’ – Wikipedia. We’re told these electromagnetic forces stretch for 24,000 light years in one galaxy, but understanding them is still in its infancy.
New observations from SOFIA are shedding light on how spiral-shaped galaxies, like our own Milky Way, get their iconic shape, says NASA.
Our Milky Way galaxy has an elegant spiral shape with long arms filled with stars, but exactly how it took this form has long puzzled scientists. New observations of another galaxy are shedding light on how spiral-shaped galaxies like our own get their iconic shape.
Magnetic fields play a strong role in shaping these galaxies, according to research from the Stratospheric Observatory for Infrared Astronomy, or SOFIA.
Scientists measured magnetic fields along the spiral arms of the galaxy called NGC 1068, or M77. The fields are shown as streamlines that closely follow the circling arms.
“Magnetic fields are invisible, but they may influence the evolution of a galaxy,” said Enrique Lopez-Rodriguez, a Universities Space Research Association scientist at the SOFIA Science Center at NASA’s Ames Research Center in California’s Silicon Valley. “We have a pretty good understanding of how gravity affects galactic structures, but we’re just starting to learn the role magnetic fields play.”
The M77 galaxy is located 47 million light years away in the constellation Cetus. It has a supermassive active black hole at its center that is twice as massive as the black hole at the heart of our Milky Way galaxy. The swirling arms are filled with dust, gas and areas of intense star formation called starbursts.
SOFIA’s infrared observations reveal what human eyes cannot: magnetic fields that closely follow the newborn-star-filled spiral arms.
This supports the leading theory of how these arms are forced into their iconic shape known as “density wave theory.” It states that dust, gas and stars in the arms are not fixed in place like blades on a fan. Instead, the material moves along the arms as gravity compresses it, like items on a conveyor belt.
The magnetic field alignment stretches across the entire length of the massive, arms — approximately 24,000 light years across.
This implies that the gravitational forces that created the galaxy’s spiral shape are also compressing its magnetic field, supporting the density wave theory.
The results are published in the Astrophysical Journal.
Full article here.
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Harvard-Smithsonian Center for Astrophysics: What ionized the universe? [2019]
Quote: The sparsely distributed hot gas that exists in the space between galaxies, the intergalactic medium, is ionized. The question is, how?
. . .
The result…suggests that a serious reconsideration of the ionizing budget of the intergalactic medium of the universe is needed.
via Tallbloke’s Talkshop
December 10, 2019 at 01:27PM
Iowa Climate Science Education 