Galaxies

In Proverbs 25:2, it says “It is the glory of God to conceal a matter; to search out a matter is the glory of kings (NIV84).” We like to think we can figure out the universe. Sometimes I wonder if God is sitting back laughing at how little we understand about what He made. Today’s technology used in astronomy research is truly amazing. For example, some researchers in Spain recently used a new satellite called Gaia to do what you could call an actual measurement that seems to show our galaxy, the Milky Way, is a Barred Spiral in its shape. Click here to read about this. We can obtain all sorts of pictures of objects in space. Computers can simulate cataclysmic events in space like galaxies colliding and watch what happens. We can figure out the distances to the stars, what they’re made of, how they are clustered together, and the speed and direction of their motion. There are always limits to how precise we can be, but there is a bigger limitation in how we figure out things in astronomy. We should be mindful of how limited we are as human beings. We weren’t there at the beginning of the universe. So there is much we haven’t actually seen because we weren’t there in the past. We don’t have a video of what was happening at the beginning of the universe. Also, there is a lot of assumptions and interpretation that goes into inferring what happened in the past, based on what we see and measure in the present.

Galaxies were an unexpected thing in the early days of science. Johannes Kepler and Tycho Brahe never imagined galaxies in the early 1600’s. Telescopes had to improve for a long time before people figured out that galaxies were actually gigantic collections of stars. Our galaxy was called the Milky Way long before anyone knew what it was. For many years people thought it was a nebula, a cloud in space. So mankind’s understanding of galaxies has come a long way. Even just a few years ago, scientists estimated the number of stars in our galaxy to be something like one half to one fourth the number scientists believe today. Today estimates run in the range of 200 to 400 billion stars just in our own galaxy. Galaxies represent a surprising level of organization of stars in the universe. Scientists still debate a fundamental chicken and egg question about galaxies. Which came first, the stars or the galaxies that the stars are within. In other words, do galaxies form from the top-down or from the bottom-up? The current leading answer to this is the bottom-up approach. Scientists today would say stars formed first and then stars clustered together, clusters grew into galaxies, and eventually galaxies merged together to form bigger galaxies.

Galaxies come in many shapes, sizes, and colors. There are spiral galaxies, elliptical galaxies, and others that are just called “irregular” in shape. Our galaxy is a special kind of spiral galaxy called a Barred Spiral because there is what looks like a straight strip of stars that goes through the center of our galaxy’s central bulge. Then from the ends of the straight strip, the galaxy has spiral arms like other spiral galaxies. Many galaxies are of odd shapes and there are pairs or groups of galaxies that are near each other or they may even blend together. Galaxies have a lot empty space, so they can pass right through each other. But, if they do this, it can generate fireworks and they distort each other’s shapes. Scientists tend to judge the age of a galaxy from the color of the stars that predominate in it and from the question of how much dust is in it. White and blue stars are assumed to be younger and yellow and red stars are assumed to be billions of years older. I would say these differences are more about how they were created, not their age. Also if a galaxy is very large, it is thought to be older as well. Scientists believe galaxies have collided and merged together and this is how galaxies grow over billions of years.

How do galaxies relate to the Big Bang?
Actually the Big Bang theory does nothing to explain how galaxies actually form. But the models scientists have for galaxy formation are like an addon to Big Bang models. Some scientists would say that it could take 3 to 6 billion years for large galaxies like we often see today to form. This also implies that the early universe not long after the Big Bang should have mostly small galaxies, not big ones that look like today’s galaxies. But this has not been what scientists have discovered as they get better telescopes that peer farther and farther out into the universe. The formation of galaxies is a tough problem if you leave out a Creator-God. Even more so, the formation of large superclusters of clusters of galaxies is an even tougher problem. (See the article and podcast about ‘Things too big for the Big Bang.’)

In 1988 a well known physicist, James Trefil, made this statement about galaxies and the Big Bang:

“It has always been difficult for astronomers to explain why stars are clumped into galaxies instead of being spread out more uniformly in space… There shouldn’t be galaxies out there at all, and even if there are galaxies, they shouldn’t be grouped together the way they are….
The problem of explaining the existence of galaxies has proved to be one of the thorniest in cosmology. By all rights, they just shouldn’t be there, yet there they sit. It’s hard to convey the depth of the frustration that this simple fact induces among scientists.”

So since 1988 scientists have worked on the problem some. But occasionally scientists still comment about the questions of the formation and evolution of galaxies being an unsolved problem. In an article in the journal Nature from 2004, several scientists said this:

“Nearly a century after the true nature of galaxies … was established, their origin and evolution remain great unsolved problems of modern astrophysics.”

There are some very technical aspects of galaxy formation that researchers have spent time and effort on. But I don’t think astronomers have a good handle on galaxy formation because there are so many layers of assumptions that sort of ‘cloud’ the issues. One of those issues is the topic of dark matter.

What is dark matter?
Dark matter is believed by astronomers and physicists to be some form of exotic particles that don’t interact much with normal matter. It is thought to be very hard to detect because it doesn’t interact with light or normal matter much. Not all physicists and astronomers believe in dark matter, but most do. Dark matter is used in many computer simulations and in cosmology calculations, and it is assumed to make up most of the mass of most galaxies. But there is one big problem with dark matter. Particle physicists can’t find observational evidence for it. There have been a number of proposed exotic forms of matter that physicists suggested but these theories so far have no clear evidence. What is the evidence for dark matter? The primary argument for it has been the velocities of stars in galaxies.

In our solar system, the planet orbits follow a predictable mathematical law discovered by Johannes Kepler that tells us how the velocity of a planet along it’s orbit decreases the farther away from the Sun the planet is. Planets, moons, asteroids, and other objects in our solar system follow Kepler’s laws of orbital motion beautifully. But the stars in a spiral galaxy don’t quite follow the same pattern. If you measured the speed of stars moving in the plane of a spiral galaxy, and compare these speeds going from the inner part near the galaxy center outward toward the edge, a funny thing happens. The star velocity is nearly constant for a long way moving outward from the center of the galaxy. But as you get beyond a certain distance, the velocities of the stars increase. This brings up a problem because if the galaxy is billions of years old, why are the outer stars still there? The galaxy would come apart over time. Also, in spiral galaxies the spiral arms tend to “wrap up on themselves” over time. So I think this suggests they could be much younger than most astronomers think.

Scientists debate the possible explanations of the galaxy star velocities to this day. But the answer most astronomers believe is that there is dark matter that makes up a large part of the mass of the galaxy, though we can’t detect it. So this dark matter would be distributed in and around the galaxy in a way that is different than the stars we see, so it is thought to explain the odd motion of the outer stars. I think the assumption that the galaxies are billions of years old is wrong. But if there were real evidence for detecting dark matter so that we knew what kind of particles it was, I could perhaps be persuaded. But without that, I’m skeptical. There have been some cases of galaxies that have been claimed to be evidence of dark matter, but I don’t buy those claims because there have been critics of those cases and I think there are other ways to interpret the evidence. I’m also skeptical when scientists say that maybe 90% of the mass of a galaxy is dark matter and only 10% is normal matter we can detect or see. This is not believable to me. It’s interpreting what we see incorrectly somehow. Most of the matter must be in the stars. Certainly there could be exotic forms of matter we don’t know of, but it seems to me that modern science makes way too much out of dark matter when we can’t even detect it or explain what it is. To read a couple of good articles about the lack of evidence for dark matter, click here and here. If you want to try a very interesting Goggle search, try searching for “Dark matter doesn’t exist.” There are many videos and articles saying this and they are from intelligent people including some astronomers.

There are some very strange and interesting looking galaxies. Many of them look like two or more galaxies have collided or have come close to each other and have distorted each other. Creationists have some differing opinions about these galaxies. I would lean toward the view that they were created essentially as we see them. But I think we should not get so hung up on the scientific questions they raise that we can’t just sit back and say “Wow! God made this!” There are many mysteries about the universe we haven’t figured out yet. There is nothing too large in the universe for God to be able to control it. Also, it may be at least as important that we can sit back and enjoy the beauty of the universe as it is that we understand it. In fact, we really should think of God as like an artist when we see pictures of galaxies and nebulas in space. Sometimes God created things very orderly and sometimes he seems to have created with a bit of chaos or with what you might call “artistic flourish.” A human artist painting on a small canvas may flick his wrist and create a splash or curve of color on the canvas. But God’s canvas was the universe. With a “flick of his wrist” He could spread stars across a million light-years!

Below are some links to some interesting galaxies:

MACS J0717
Considered a galaxy cluster. This cluster is thought to have formed from the collision of four other galaxies. But no one has actually seen such a collision, it is inferred by scientists. The image below combines a picture from the Hubble Space Telescope to show the white galaxies with an X-Ray image from the Chandra X-Ray Observatory. The blue color shows gas of the highest temperature, with purple showing lower temperatures.
https://hubblesite.org/image/2539/gallery

i-Zwicky-18
Considered a dwarf irregular galaxy. It is also called a starburst galaxy. It is much smaller than our galaxy, the Milky Way, at only 3,000 light-years in diameter. Scientists generally judge the age of a galaxy by the color of the stars in it. Bright white and blue stars are thought to be young. But yellow stars are older. This galaxy has a mix of both young and old stars, by this way of thinking. The yellowish nearby galaxies would be considered old. But how do we know that star color is an indication of age? If this galaxy is old, it is a mystery why it is so blue. The blue color is believed to indicate star formation. Thus scientists debate what would cause so much star formation.
https://apod.nasa.gov/apod/ap071017.html

The Antennae Galaxies
This is thought to come from a collision and merger of two spiral galaxies hundreds of millions of years ago. These two galaxies have designations NGC 4038 and NGC 4039. But what if God just made it this way? It is wild but beautiful. To me, it looks like a bent over tadpole with lights.
https://www.nasa.gov/multimedia/imagegallery/image_feature_1086.html

The Milky Way
What about our own galaxy – the Milky Way? Here are some numbers on our Sun’s motion orbiting the center of the galaxy, and the Milky Way’s motion through space. You may think you’re sitting still to read this, but you’re not. Our Sun orbits the center of the Milky Way (a barred spiral) about 26,000 Light-Years (LY) from the center. This means our Sun is moving in a circular orbit at around 225 kilometers (km) per second (or 140 miles per second) around the galaxy. Earth orbits the Sun while the Sun orbits the galaxy. Our galaxy is also moving at a speed of 552 km per second (343 miles per second) with a ‘local’ group of galaxies. Our galaxy is also in a collision course with the Andromeda galaxy. But they wouldn’t collide for billions of years. Since everything is in motion in this way, think of what God must have done when he created Earth before the Sun, Moon, and stars. I would guess he created the Earth already in its motion first then put the Sun, Moon, stars and the galaxy in place already in motion as they were created on the fourth day. This is a mind-boggling dynamics problem. This way Earth would not undergo massive geological forces from being accelerated into motion. Of course, God could solve these kind of problems however he wanted. This is only my speculation. After all, I wasn’t there.

We are placed at a good spot in our galaxy for observing the rest of the universe. If we were in or near the central bulge of the galaxy, there would be too much scattered light from dust and gas for us to see out beyond our own galaxy. But since we lie in a region between two spiral arms, it’s a good spot for seeing the universe. In the center of our galaxy is a supermassive black hole, called Sagittarius A. Sagittarius A contains the mass of about 4.3 million Suns. Black holes are strange but very real. The observational evidence for them is very good. The central black hole seems to act like a kind of anchor for the galaxy. There is one other thing about our galaxy that is a bit unusual, it has two satellites orbiting it. These are called the Large and Small Magellanic Clouds, but they are actually considered dwarf irregular galaxies. These can’t be seen from the Earth’s Northern Hemisphere.

I think we should think of God as an artist when we think of the variety of wonders out in space. Young age creationists have multiple ways of understanding what we see in space. Some would take the view that God created things pretty much as we see them and they have not had time to change much since the beginning. Others would argue that during the creation week there could have been some acceleration of processes, or time dilation, that made things happen very rapidly on the fourth day of creation week. I tend to take the first view. I think we cannot tell if the universe is young or old by just looking at it. But the Bible does imply the universe is only thousands of years old. There are some interesting scientific puzzles to unravel yet regarding this but I will always side with the Bible.


Image of galaxy UGC 12158 (NASA/ESA). This is a Barred Spiral, thought to be similar to our own galaxy, the Milky Way.

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