Astronomers have discovered that stars in a distant galaxy move at stunning speeds — greater than 1 million mph. These hyperactive stars move at about twice the speed of our sun through the Milky Way, because their host galaxy is very massive, yet strangely compact. The photo above, which has theorists baffled, is 11 billion light-years away. It is the first time motions of individual stars have been measured in a galaxy so distant.
While the stars' swiftness is notable, stars in other galaxies have been observed to travel at similarly high speeds. In those situations, it was usually because they were interlopers from outside, or circling close to a black hole.
But in this case, the stars' high velocities help astronomers confirm that the galaxy they belong to really is as massive as earlier data suggested.
The compact nature of this and similar galaxies in the faraway early universe is puzzling to scientists, who don't yet understand why some young, massive galaxies are about five times smaller than their counterparts today.
Yale University astronomer Pieter van Dokkum said, "A lot of people were thinking we had overestimated these masses in the past but this confirms they are extremely massive for their size. These galaxies are indeed as bizarre as we thought they were."
Scientists used the new velocity measurements, conducted with the Gemini South telescope in Chile and the Hubble Space Telescope, to test the mass of a galaxy identified as 1255-0. The sun's gravity determines the orbiting speed of the Earth, likewise the galaxy's gravity/mass determines the velocities of the stars inside it.
The researchers found that indeed, the galaxy is exceptionally dense. Galaxy 1255-0 is 11 billion light-years away. 30 to 40 percent of galaxies from this time period are compact like this one. But in the modern, nearby universe, astronomers don't find anything similar.
Somehow, high-mass galaxies from the young universe grow in size but not in mass – they spread out but maintain their overall heft – to become the high-mass galaxies we see today.
van Dokkum said, "It's a bit of a puzzle, we think these galaxies must grow through collisions with other galaxies. The weird thing is that these mergers must lead to galaxies that are larger in size but not much more massive. We need a mechanism that grows them in size but not in mass."
So far, such a mechanism is elusive, (Ah, the mind of God, sometimes the more we know, the less we seem to know.) but astronomers have some ideas. Perhaps these galaxies expand their girth by merging with many small, low-mass galaxies. Or maybe these galaxies eventually become the dense central regions of even larger galaxies.
van Dokkum said, "It could also still be that we are doing something wrong but I think at the moment you could say that the ball is somewhat in the court of the theorists. Hopefully they can come up with some kind of explanation that we can test further."
It is nice to hear a scientist like van Dokkum admit we humans could be wrong. We are only beginning to get a glimpse of the unfathomable mind of our Creator, our Intelligent Designer. It is he who is providing our giant leap in knowledge of his universe. The earth's position in the Milky Way allows us to view other parts of the universe. Indeed, if we were in a different position in our Milky Way cosmic dust would block our normal view of God's majestic universe. In fact, we could not pierce through the dust to view the core of our Milky Way without Infrared, Gamma and X-Ray cameras and devices.
But in this case, the stars' high velocities help astronomers confirm that the galaxy they belong to really is as massive as earlier data suggested.
The compact nature of this and similar galaxies in the faraway early universe is puzzling to scientists, who don't yet understand why some young, massive galaxies are about five times smaller than their counterparts today.
Yale University astronomer Pieter van Dokkum said, "A lot of people were thinking we had overestimated these masses in the past but this confirms they are extremely massive for their size. These galaxies are indeed as bizarre as we thought they were."
Scientists used the new velocity measurements, conducted with the Gemini South telescope in Chile and the Hubble Space Telescope, to test the mass of a galaxy identified as 1255-0. The sun's gravity determines the orbiting speed of the Earth, likewise the galaxy's gravity/mass determines the velocities of the stars inside it.
The researchers found that indeed, the galaxy is exceptionally dense. Galaxy 1255-0 is 11 billion light-years away. 30 to 40 percent of galaxies from this time period are compact like this one. But in the modern, nearby universe, astronomers don't find anything similar.
Somehow, high-mass galaxies from the young universe grow in size but not in mass – they spread out but maintain their overall heft – to become the high-mass galaxies we see today.
van Dokkum said, "It's a bit of a puzzle, we think these galaxies must grow through collisions with other galaxies. The weird thing is that these mergers must lead to galaxies that are larger in size but not much more massive. We need a mechanism that grows them in size but not in mass."
So far, such a mechanism is elusive, (Ah, the mind of God, sometimes the more we know, the less we seem to know.) but astronomers have some ideas. Perhaps these galaxies expand their girth by merging with many small, low-mass galaxies. Or maybe these galaxies eventually become the dense central regions of even larger galaxies.
van Dokkum said, "It could also still be that we are doing something wrong but I think at the moment you could say that the ball is somewhat in the court of the theorists. Hopefully they can come up with some kind of explanation that we can test further."
It is nice to hear a scientist like van Dokkum admit we humans could be wrong. We are only beginning to get a glimpse of the unfathomable mind of our Creator, our Intelligent Designer. It is he who is providing our giant leap in knowledge of his universe. The earth's position in the Milky Way allows us to view other parts of the universe. Indeed, if we were in a different position in our Milky Way cosmic dust would block our normal view of God's majestic universe. In fact, we could not pierce through the dust to view the core of our Milky Way without Infrared, Gamma and X-Ray cameras and devices.
No comments:
Post a Comment