Images from the James Webb Space Telescope

August 25, 2022 waynespencer Leave a comment

Recently in mid-July 2022 we began to see images from the James Webb Space Telescope. The new images are generating excitement and new questions in the scientific community. It is always exciting when new technology allows us to see something mankind has never seen before. The more we discover, the more new puzzles and mysteries are encountered as well. First of all, who was James Webb? He was administrator of NASA during the Apollo Mission years and gained a great reputation for helping accomplish important discoveries in space science. To go to the NASA official website for the James Webb Telescope, see https://www.jwst.nasa.gov/.

The James Webb Telescope (or JWST) is an infrared telescope and the successor of the Spitzer Space Telescope. Infrared telescopes are more effective from in space where they can be kept very cold. The JWST has several sheets of material that shield it from heat radiating from the Earth and the Moon. It has been placed at a special location known as L2, which is one of the “Lagrange Points” for Earth. In this location gravity makes it quite stable and it is never in direct Sunlight since Earth lies between it and the Sun. The James Webb telescope is said to be so sensitive that it could detect the heat given off by a bumble bee at a distance to the Moon! The JWST has 18 mirrors that are very precisely aligned to look in the same direction. Thus it collects digital image data and the data is magnified in a way that is essentially like stacking the 18 images on top of each other. There are three ranges of infrared wavelengths in the electromagnetic spectrum that can be viewed by the Webb telescope. Since all these wavelengths are invisible to our naked eyes, scientists essentially shift them to the visible range as desired to allow us to see them. Thus, the images generated do not show the objects in their “real” or “natural” colors, rather scientists can pick the colors to show different types of detail, depending on what they are wanting to study. This is how an infrared telescope is used and it makes for some beautiful images that are interesting to compare to the images from other telescopes like the Hubble Space Telescope, for example.

Webb’s First Deep Field

The Hubble Space Telescope was famous for its “Deep Field” images in long exposures of a piece of ‘dark’ sky. So, it’s not surprising one of the first images released on July 11 by the JWST has been called the Webb’s First Deep Field (shown below cropped and resized). It is a composite image that took a total of 12.5 hours. It captures galaxies farther away than anything the Hubble Space Telescope could obtain. It is mostly an image of galaxies, but there are some stars at relatively nearby distances that show up with spikes. The stars with diffraction spikes are not important, they are only an artifact of the telescope. The telescope is really looking at what lies behind the stars with spikes. Near the center of the image to the lower right of the large spikes is galaxy cluster known as SMACS-0723. This galaxy cluster is massive enough to bend the light from galaxies behind it. So, the galaxy cluster is magnifying and bending light from the galaxies behind it. This is an example of gravitational lensing, something Einstein predicted. The lensing effect causes the distant galaxies light to be smeared out in an arc. The arcs look almost concentric around the large cluster.

JWST SMACS-0723 — Galaxy cluster SMACS-0723. Shows gravitational lensing of very distant galaxies.

Stephen’s Quintet

Next is a very famous group of galaxies that are interacting known as Stephen’s Quintet. It gets its name from five galaxies. In the James Webb image, three of the large galaxies show up in somewhat different colors, one greenish, one blue, and the one on top is purple and reddish. The blue elliptical shaped galaxy is nearer to us than the others. But these galaxies are distorting each other’s shapes and pulling gases and stars off of each other. The one above the others with red and purple apparently collided with the greenish one. The JWST provides a unique view of Stephen’s Quintet. This image is from the MIRI instrument, which is seeing mid-infrared light. This means it is looking through some layers of dust and gas to see deeper inside.

The JWST image of Stephen’s Quintet above is interesting to compare with another image of the same thing, below. The image below is Stephen’s Quintet viewed with a combination of X-Rays and Visible light. There are distorted galaxy arms and a blue shock wave visible in this image that are not visible in the James Webb image above. This shows how the MIRI instrument can see through outer material. The same region of sky around Stephen’s Quintet can look very different, when you are seeing different portions of the electromagnetic spectrum. There are actually more than five galaxies in these images. Astronomers have been fascinated by the Quintet for a long time.

This image shows Stephens Quintet in X-Rays and optical light. Rotated about 45 degrees counterclockwise compared to the JWST image above.

The Southern Ring Nebula

Next is an interesting pair of images, both from the JWST. The Southern Ring Nebula is shown below using two different ranges of wavelengths in infrared light. The left image is from NIRCam, the James Webb telescope’s near infrared camera. This camera uses lower wavelength light, which is of higher energy. Then the image on the right is the MIRI instrument, for mid-infrared light. The mid-infrared uses higher wavelengths, which are of lower energy. So, its like NIRCam sees the hotter material and MIRI sees through the outer layers to the cooler material within. The Southern Ring Nebula has two stars within it that orbit each other. The two stars can be seen in the image on the right. The star that looks less bright has already shed some of its material to make the nebula. The other star (brighter) may do the same, some day. We are basically looking at the nebula end-on. If we could see it from a side view, it would look like two bowls stuck together at the bottom, with a hole in their centers where the stars are. Space telescopes not only help us see what we could not see with the naked eye, they allow us to highlight different elements in the gases or see particular features by studying the light spectrum from the object.

JWST Southern Ring Nebula — Two JWST images of the Southern Ring Nebula. Left image is in near-infrared. Right image is mid-infrared.

NIRSpec and Spectroscopy

One of the great technical innovations with the James Webb telescope I think is what’s called NIRSpec, for near-infrared spectroscopy. Spectroscopy breaks down or splits the light into its component wavelengths (like a prism but JWST has something way beyond what a prism does). So, spectroscopy allows astronomers to determine what chemical elements are present in what they see. What is more, the JWST NIRSpec instrument can observe 100 objects at the same time! There is a sophisticated micro-shutter system operated magnetically where each micro-shutter is about the width of a human hair. With this system two objects may be near each other in the sky but one could be blocked out and the other measured in a very precise way. The spectroscopic measurements of the JWST will be very important for study of nebulas and dust, extrasolar planets, and other objects. I’m particularly interested in what the Webb telescope discovers about exoplanets. Already, the JWST has done transit measurements of one exoplanet, WASP-96b. This exoplanet is only 1/9 of the distance to its star as Mercury is to our Sun. It is a gas planet of about ½ of the mass of our planet Jupiter but it is about 20% larger than Jupiter in size. It is very “puffed up” and close to its star. WASP-96b requires only 3 ½ Earth days to orbit its star. The Webb telescope gathered spectra as WASP-96b passed in front of its star. This spectra showed very clear evidence of water vapor in the planet’s gases. This is not the first evidence of water in an exoplanet but the extraordinary thing is the clarity of the data from the Webb telescope.

Surprising Galaxies

So far the main surprise to scientists from the James Webb Space Telescope comes from very distant galaxies that have been detected. There’s likely to be much more debate in the scientific community about these findings. The JWST has detected evidence for the most distant galaxies ever observed. The greatest distances in the universe are often expressed in terms of redshift. The redshift is expressed as a number; before the JWST, the most distance galaxies might have had a redshift value of 11-13. But even though it’s been only a few weeks since images started being released, the JWST is making a stir over distant galaxies. In some things our beliefs tend to determine what surprises us. Thus, there’s a need to understand a bit about Big Bang theory to understand what is surprising about the JWST images.

In the Big Bang theory, the universe begins with a hot fireball and a very rapid expansion of space. In the Big Bang model, it takes a few hundred thousand years for the expanding fireball to cool down enough that hydrogen atoms can form. When hydrogen can form and remain stable this is known as the decoupling of matter and radiation. From this time forward, the universe cools down as it expands. But all there is initially is hydrogen gas. There were no stars or galaxies or nebulas. But there were regions more dense than others and it is thought that gravity would begin forming clumps of matter. There has been a long debate among cosmologists over which came first, stars or galaxies. The general consensus today is that the first stars formed first, perhaps often in clusters, and then they collected together into galaxies. This is a process that requires a lot of time. The process is ill-defined actually and is very much still a mystery to scientists. How much time would it take to form the first galaxy? It’s thought that the earliest stars may have formed about 180 million years after the Big Bang. This means that in Big Bang theory, after the universe expands and cools down, there would be a period in which there are not yet any stars or galaxies. Then if the above scenario is correct, stars would have to form and then collect together into galaxies. So this period in which there was not yet any stars or galaxies has been referred to as the “dark age” of the universe.

The significant thing about the JWST is that it is thought to be able to see back to about what would be the approximate end of the “dark age”. So has JWST seen the end of galaxies? Not yet. Case in point is an object labeled as CEERS-93316; it is known officially as a “galaxy candidate.” Its redshift is 16.7, which scientists would say this puts it at about 250 million years after the Big Bang. There may be other “candidate galaxies” detected by JWST with redshifts of as much as 18. We may have to wait and see if these numbers are confirmed by other researchers. But, this is way out there!! By known effects such as gravity, it is challenging to explain how galaxies could form so early after the Big Bang. JWST will give better information on these distant objects than we have had before, thus these distant galaxies are going to be objects of much scrutiny. One scientist studying CEERS-93316 expressed the problem as below:

“The observations of this galaxy push observations back to the time when we think the first galaxies ever to exist were being formed. Already we’ve found more galaxies in the very early Universe than computer simulations predicted, so there is clearly a lot of open questions about how and when the first stars and galaxies formed.”
(To read more on this go to https://phys.org/news/2022-08-farthest-galaxy-broken-million-years.html )

Unlike what many Christians in the sciences say, I think the Bible conflicts completely with the Big Bang. The Bible doesn’t describe technical details of the beginning of the universe but it does give a time frame. The Earth and universe were completed in a week, from God’s miraculous activity. This implies that galaxies did not require a long process to form from gravity collecting stars together. Everything was complete and ready for the first man and woman when they were made on the sixth day. Thus, I suspect JWST will not see the end of galaxies. The most distant galaxies will look like galaxies usually look. But there could be surprises; there always are when we get to see with new technology. I think believing God created miraculously is more believable than believing that natural forces and processes did it all. Natural processes are just not up to the task of forming a universe.

Images: Public domain from NASA & the Space Telescope Science Institute (cropped and resized)

Science Related

Stellar fireworks

May 2, 2022 waynespencer Leave a comment

Novae, Supernovae, and Related Cosmic Catastrophes

I’ve always been fascinated with fireworks. It seems to also be a general characteristic of people who study physics – physicists like to study things that blow up! There are some really powerful events that happen to stars from time to time that fascinate astronomers. These are of several types but are referred to under the terms “nova” and “supernovae.” The universe contains so many mysterious things and it is dynamic, not static. It seems to me that God also likes fireworks, but He makes his fireworks really big! There are a few other variations on these two terms, some of which are fairly recent discoveries, such as “micronovae,” “kilonovae,” and “macronovae.” This article will explain some on what these are. Note that to say “nova” or “supernova” is singular, but “novae” and “supernovae” are plural terms.

“He determines the number of the stars and calls them each by name. Great is our Lord and mighty in power; his understanding has no limit.” Psalm 147:4

In considering the Creator, we have an interesting statement in Psalm 147:4 above. In nova events a star temporarily brightens for some period of time and then goes back to normal. In supernovae, a star goes through a catastrophic permanent change where it becomes a different kind of object after some of it is blown out into space in the explosion. In some supernovae, the star can be completely destroyed. There are also events where stars can merge together into one object, causing a massive explosion. Scripture implies God is in control of the explosions of stars and of events that change the number of the stars. When there are supernovae, we should be very glad that they are so far away.

Supernova Remnant Cassiopeia A, viewed by Tycho Brahe in 1572. Mosaic from NASA/CXC/SAO.

In 1572, astronomer Tycho Brahe coined the term “stella novae” when he saw what we now call supernova SN-1572. Novae and supernovae can look similar to the naked eye (if they are visible to the naked eye). A known star becomes much brighter and then fades or changes its appearance. In Tycho’s day, people were still influenced by the ideas from Aristotle. At that time people believed that anything in outer space beyond the Moon never changed. The universe outside of the Moon was supposed to be immutable and never change. But Tycho saw what seemed like a new star appear in the constellation Cassiopeia that hadn’t been visible before; and, it was brighter than Venus! He tried to estimate the distance to it (using parallax) but it was too far for him to measure. So, he concluded correctly that it was farther away than the Moon. So he had seen something change in space that wasn’t supposed to happen! This is why Tycho Brahe made the following statement: “I doubted no longer. … In truth, it was the greatest wonder that has ever shown itself in the whole of nature since the beginning of the world, or in any case as great as [when the] Sun was stopped by Joshua’s prayers.”

It took many years for astronomers to figure out what these “new stars” were. First, I will explain nova and supernova Type Ia because they are similar in some respects. A nova occurs when a white dwarf star is bound to a normal star (a binary star system). If the normal star gets close enough to the white dwarf matter may be pulled off the normal star onto the white dwarf. The white dwarf is a star that has compressed over time due to gravity and has used up its fuel, and it is very dense and hot. If a stream of gas falls onto the white dwarf but it is not enough to envelope the white dwarf completely, it is possible for nuclear fusion to trigger in a localized spot on the white dwarf’s surface. This gives off a powerful flare of light and energy that can make the star look much brighter. This is a nova. A Type Ia supernova is relatively rare but it also involves a white dwarf pulling matter off of another star. In a Type Ia supernova, the gas falling on the white dwarf is much more, enough to envelope and put pressure on the white dwarf. Type Ia supernova are not totally understood though. But for Ia events there will be a runaway nuclear fusion process that causes a massive explosion. This explosion can be great enough to completely destroy the white dwarf star. An explosion like this also sends out a powerful shockwave into space.

Supernovae that are of Type II, Type Ib and Ic are also similar to each other. An important fact about the Type I supernovae events is their light shows there’s no hydrogen in the explosion. Hydrogen is easily detected in the light spectrum, if present. However Type II supernovae do have evidence of hydrogen. A Type II supernova does not happen due to two stars interacting but is more related to a star reaching what you could call its “old age” where it is running out of hydrogen fuel. Running out of hydrogen sets off changes in the star that depend on how massive the star is. So, a Type II supernova is called a “core collapse” supernova because this is what happens inside the star. In just a few seconds the core of the star can collapse and this creates forces that cause it to explode. A Type II supernova happens in a star that is between 8 and 40 times the mass of our Sun. These explosions give off great energy and some of them, if seen from Earth could be visible in the daytime, even in bright sunlight. But scientists cannot actually predict when a supernova will happen. The star Betelgeuse (in the constellation Orion) is a red supergiant star and scientists suspect it is nearing the end of its hydrogen, which means it could explode. Some have said it could happen in 2022. But we really have no way of knowing. To a star, “soon” could mean a thousand years from now.

A star nearing its “old age,” running low on hydrogen starts using other elements for fuel. This causes the star to stratify into layers (like the layers of an onion) where the various layers are each more concentrated in a certain element. The highest pressures and temperatures near the center could form some of the higher atomic weight elements. The highest atomic number element able form inside a star is Iron, so it would be near the center. Then going from the center outward there can be Silicon, Magnesium, Neon, then Oxygen, then Carbon, then Helium, then hydrogen that is not as hot and cannot fuse into Helium. There may be other elements from the periodic table that form also if the temperatures are high enough. In a Type Ib supernova, the outer Hydrogen layers can be used up or thrown off before the explosion, leaving the Helium layer as the outermost layer, until the star collapses and then explodes. In a Type Ic supernova, the outer layers of Hydrogen and Helium are used up or thrown off making Carbon the outermost layer. Then if massive enough gravity causes the star to collapse and then it explodes.

NASA/ESA Hubble Space Telescope image of a Luminous Red Nova. These form from the collision of two normal stars.

Another type of event has a couple of names, Kilonova or Macronova. These are thought to come from when two dense objects collide and merge together (not normal stars but possibly one of them being a neutron star and another one maybe a white dwarf). They create a lot of light but the visible light is followed by infrared and other types of radiation. The collision of dense objects like this is one of the events that scientists use to search for gravitational waves. Gravitational waves are ripples in the fabric of space as Einstein described them. These Kilonova/Macronova events are thought to create a lot elements from the periodic table above Iron. Another kind collision and merger of two normal stars is a less powerful explosion but is called a luminous red nova. In a luminous red nova, normal stars merge into a red giant star. These create beautiful nebulas with a bright red star in the center. Thus, as man-made fireworks can make for great pictures if you can capture them, so can God’s fireworks out in space.

Crab Nebula SNR — Image of the Crab Nebula supernova remnant. This came from a supernova in 1054 A.D. From NASA, STScI, and ESA.

When have supernovae been actually seen in history? In 1054 a supernova happened that was witnessed by the Chinese, Japanese, and by American Indians. This one created the supernova remnant nebula we call the Crab Nebula (pictured above). Beautiful pictures have come from this massive explosion. Another famous one was not so long ago, in 1987. Now called SN-1987A (‘A’ because it was the first one of that year.) Astronomers studied 1987A a great deal. Some hours before it was seen neutrinos were detected. Then some months later we began to see rings of hot gas expanding away from it. It was eventually determined the star that exploded was called Sanduleak -69 202. Sanduleak was about 168,000 Light-Years away in the Large Magellenic Cloud, which is a small galaxy orbiting our galaxy, the Milky Way.

This image, from the Hubble Space Telescope in 1995, shows the orange-red rings surrounding Supernova 1987A in the Large Magellanic Cloud. The supernova explosion occurred in February 1987.

In observing supernovae over the years, astronomers have found an interesting way to detect that a supernova has happened sometime in the past. They can look for light emissions from a radioactive isotope of Aluminum. This was reported in a paper from the Royal Astronomical Society in July 2020, from a research project of the ESA. Aluminum-26 (Al-26) is found in the shockwaves from supernovae explosions. It seems to be a very good way to “look for” supernovae. But this has lead to a recent discovery that is a mystery about our own Galaxy, the Milky Way. There is evidence of Al-26 around our galaxy but it doesn’t fit what scientists would have expected. There is something called the scale height that is a measure of how a gas fades away with distance from an object. So if it fades away quicker it has a lower scale height, but if it fades away slower it has a bigger scale height. Or if the gas is more dense it has a bigger scale height. Alumnium-26 is observed to have a scale height of 800 for above the disk of our galaxy. If this Al-26 came from stars in our galaxy going supernova, scientists would expect the scale height to be only about 50. So it raises the question, where does all the Al-26 come from? Secondly, the Al-26 around the galaxy is moving faster than the galaxy disk. The spiral arms of the galaxy rotate around the center of the galaxy at a certain speed based on the distance from the center. But the Al-26 is essentially rotating about 100 to 200 km/second faster than the galaxy disk spins. This is puzzling to scientists because scientists tend to assume that all the Al-26 comes from supernova in the galaxy. But if that is the case, why is it moving faster than the galaxy? The researchers are suggesting the Al-26 comes from outside our galaxy.

God displays his greatness in the vastness and the mysteries of our universe. He creates beauty from explosions powerful beyond our understanding. There is no explosion too big for God to be in control over it. Yet, in his unlimited power, He wants a relationship with us and cares about each of us. In the work of Jesus Christ he has gone to great lengths to provide us a way to know him in a personal relationship. I want to finish this with some selections from Isaiah chapter 40 (NIV 1984 Bible).

“Who has measured the waters in the hollow of his hand,
or with the breadth of his hand marked off the heavens? . . .
Whom did the Lord consult to enlighten him,
and who taught him the right way? . . .
Surely the nations are like a drop in a bucket;
they are regarded as dust on the scales;
he weighs the islands as though they are fine dust. . . .

Do you not know? Have you not heard?
Has it not been told you from the beginning?
Have you not understood since the earth was founded?
He sits enthroned above the circle of the earth,
and its people are like grasshoppers.
He stretches out the heavens like a canopy,
and spreads them out like a tent to live in. . . .

Why do you say, O Jacob, and complain, O Israel,
My way is hidden from the Lord;
my cause is disregarded by my God?
Do you not know? Have you not heard?
The Lord is the everlasting God,
the Creator of the ends of the earth.
He will not grow tired or weary,
and his understanding no one can fathom.
He gives strength to the weary and increases
the power of the weak.”

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Christianity and Reasons for Faith – by Wayne R. Spencer