Our Earthly Flight


Our Earthly Flight
By  W. Carl Rufus

Our Earth is like a transport plane,
That carries wealth surpassing gold.
It trafficks not for paltry gain:
Its cargoes are not bought nor sold.

It holds its course around the sun;
Nor rolls, nor banks, nor stalls, nor spins.
Its yearly flight is never done;
When winter ends, the spring begins.

At eighteen-miles-per-second speed
Without an instrument in sight,
No stick to hold, no maps to read,
It travels on by day and night.

It bears a load of human freight;
From birth to death, men come and go.
They live and love, they toil and hate,
For good or ill, for weal or woe.

A billion walk its crowded ways:
And billions sleep beneath its sod.
But souls are safe through stormy days:
The unseen Pilot’s name is God.

Image credit: NASA’s Goddard Space Flight Center.

Fire Back: Where the Readers Respond

In which we discuss inflation, the multiverse, and fine-tuning.

I had the following exchange with a reader in the comments of a previous post:

jlafan2001: What is your take on the discovery of cosmic inflation? Isn’t inflation evidence of a multiverse and doesn’t that refute the fine-tuning argument?

SS: Inflation is a compelling idea that answers some big cosmological questions, and, personally I think it’s correct. One flavor of multiverse — the bubble universe idea — is an outgrowth of the inflationary big bang model. The problem for a multiverse based on inflation is that inflation is also consistent with non-multiverse models. There is currently no way to distinguish between them based on the evidence. There is, to my knowledge, nothing that can be confidently stated about the multiverse based on evidence, therefore it would be beyond foolishness to say that the multiverse constitutes a genuine refutation of the fine-tuning argument.

jlafan2001: Thank you for your input, Dr. Salviander. Why would scientists then use the inflation model as evidence for the multiverse if it can go either way?

A not unreasonable question. The answer is, inflation is one of the very few (ambiguous) lines of evidence atheist scientists have for the multiverse, and there is considerable philosophical motivation to support the multiverse no matter how weak the evidence.

There are two main problems in physics for the atheist scientist:

  1. The big bang. A universe with a beginning logically implies a supernatural creative force for the universe.
  2. The fine-tuning of the universe, for which there are only three explanations: a) necessity; b) chance; c) design.

Contrary to what Young Earth Creationists believe, atheist scientists have never been happy with the big bang. To understand why, all you have to do is go back to February of 1961 when striking evidence in favor of the big bang was presented at a meeting of the Royal Astronomical Society in London. That evidence would later turn out to be flawed, but at the time it inspired some notable headlines in London newspapers. The Evening Standard published an article with the headline “‘How it all began’ fits in with Bible story” (Peter Fairley, 10 February 1961), and the Evening News and Star featured an article headlined, “The Bible was right” (Evening News Science Reporter, 10 February 1961).

These headlines reflected the big bang’s astounding confirmation of the first three words of the Bible. To understand the significance, consider that for millennia prior to this, the scientific consensus was that the universe was eternal. Obviously, this was a big problem for the Bible-believers, but not for atheists, who rested assured that the universe required no explanation. That all started to change in the 1920s with solutions to Einstein’s general relativity equations showing the universe could be dynamic, as well as Hubble’s evidence that the universe is expanding. Things finally changed in a big way in the 1960s with the discovery of the cosmic microwave background, which pretty much sealed the deal for the big bang.

To their credit, the vast majority of physicists accepted the big bang theory once there was sufficient evidence, even if a lot of them didn’t like it. However, there were a few notable holdouts, like renowned astrophysicist and atheist, Geoffrey Burbidge. It’s not a stretch to suggest that his steadfast support for an eternal universe in spite of the evidence was philosophically motivated, especially considering he famously accused many of his colleagues of “rushing off to join the First Church of Christ of the Big Bang.”

The evidence for the big bang is by now so overwhelming that few physicists doubt it. That leaves atheist physicists with a big problem, which is how to offer an alternative to God as the supernatural creative force behind the universe. Thus, we have the multiverse.

Now, it’s important to point out that, contra what some skeptical Christians believe, physicists did not metaphorically pull the multiverse out of a magician’s hat. There are different types of multiverse (or “levels” as physicist Max Tegmark calls them), each with a basis in physics and mathematics that makes the idea conceptually somewhat compelling. One level of multiverse is the bubble universe model. This model says that inflation — a period of extremely rapid expansion of the universe shortly after the big bang — leads to regions of localized inflation, which form like bubbles in a cosmic sea of foam. Each of these bubbles expands at such a rate that they are all causally cut off from each other, and each effectively forms its own universe. This is one type of inflationary universe; there are others that do not lead to multiverses. However, as I pointed out to jlafan2001, there is no way I’m aware of that you can observationally distinguish between an inflationary bubble universe and an inflationary non-bubble universe.

So, how does this tie into fine-tuning?

The fine-tuning argument says this: the many observable parameters of the universe that permit human life to exist are so finely-tuned as to strongly imply the universe was designed by a personal being. Physicists have ruled out necessity as an explanation for fine-tuning; this means there is nothing in any physical theory or any extension of physical theory that requires the various physical parameters describing our universe to be the way they are. That leaves chance and design. For an atheist physicist, design is obviously out, which leaves chance as the only explanation. It turns out physicists aren’t very happy about this — they would have preferred necessity as the explanation — but, they’re philosophically stuck with chance. Since there is already a theoretical basis in physics for the multiverse, and chance is built into its framework, atheist physicists latch onto it as a means to explain away the appearance of fine-tuning. It also has the virtue of addressing point #1 above by providing an alternative to God as the creative force behind the universe.

The so-far insurmountable problem with the multiverse is that there is no way to test it. One of the features of the multiverse is that each of the universes within it is causally separated from all of the other universes, which means there is no way we an observe any of them, directly or indirectly. There’s just no way we can peek outside of our universe to see if there are any others. So, we’re left with ambiguous evidence like inflation and “shadow particles” (ugh). Until physicists find a way to get around this problem, which is unlikely, the multiverse remains nothing more than a science-flavored idea.

Weekly Psalm 19: Hercules A

Here is your weekly reminder of Psalm 19 — the radio galaxy Hercules A.

Hercules A is a radio galaxy — an active galactic nucleus that emits an unusually high amount of radiation in the radio part of the EM spectrum. It’s about 2 billion light-years from Earth, and is the highest radio-emitting object in the constellation Hercules. Even though this galaxy is named for the constellation in which it appears, it certainly lives up to its name — it’s about 1,000 times more massive than the Milky Way, contains a black hole that is 1,000 times more massive than the black hole in the center of the Milky Way, and, as you can see in the image, it’s shooting out radio jets that span an incredible 1.5 million light-years in length.

This image is a composite of visible light (Hercules A in the center, as well as the stars in the foreground and other galaxies in the background) and radio light (the jets and lobes). The jets and lobes are comprised of charged particles accelerated to near-light speed and twisted magnetic fields. The jets and magnetic fields emanate from a region very close to the central, supermassive black hole.

Image credit: NASA, ESA, S. Baum and C. O’Dea (RIT), R. Perley and W. Cotton (NRAO/AUI/NSF), and the Hubble Heritage Team (STScI/AURA).

Weekly Psalm 19: The Bubble Nebula

Here is your weekly reminder of Psalm 19 — the Bubble Nebula.

The Bubble Nebula is a shell of gas surrounding a massive hot star. Stellar winds from the star push the bubble of gas out, while radiation from the star excites the hydrogen gas in the bubble and causes it to glow. The magenta wisps at the bottom of the image are remnants from a star that went supernova long ago.

The nebula resides in a giant molecular gas cloud in the constellation Cassiopeia, and is about 7,000 – 11,000 light-years away. The Bubble itself is 3 – 5 light-years in size, and, if you could see it with your naked eye, would be half the apparent size of the full Moon on the sky.

Image credit:T.A. Rector/University of Alaska Anchorage, H. Schweiker/WIYN and NOAO/AURA/NSF.

Weekly Psalm 19: Centaurus A

Here is your weekly reminder of Psalm 19 — Centaurus A.

Colour composite image of Centaurus A, revealing the lobes and jets emanating from the active galaxy’s central black hole. This is a composite of images obtained with three instruments, operating at very different wavelengths. The 870-micron submillimetre data, from LABOCA on APEX, are shown in orange. X-ray data from the Chandra X-ray Observatory are shown in blue. Visible light data from the Wide Field Imager (WFI) on the MPG/ESO 2.2 m telescope located at La Silla, Chile, show the stars and the galaxy’s characteristic dust lane in close to

Centaurus A is an active galaxy, also known as an AGN (active galactic nucleus). This means an unusually large amount of energy is radiating from its central region (i.e. its nucleus) compared with normal, quiescent galaxies like our own Milky Way. There is strong evidence that every AGN is powered by a supermassive black hole actively feeding on gaseous material; that material becomes superheated as it spirals down and releases a huge amount of radiation. The supermassive black hole in Centaurus A is measured to be 55 million times the mass of our Sun.

An extreme case of an AGN is a quasar, which can outshine a thousand Milky Way-type galaxies. Centaurus A is a less-extreme type of AGN called a radio galaxy, which means it emits an unusually large amount of radiation in the radio part of the spectrum.

The image above is a composite image showing the galaxy in visible light, with submillimeter emission in orange and X-ray emission in blue. Submillimeter radiation falls between the infrared and microwave parts of the electromagnetic spectrum; neither submillimeter nor X-ray emission can be detected with the human eye, so this is what’s called a false-color image. If we had eyes that could detect this sort of emission, this is what the galaxy might look like to us.

Centaurus A is about 12 million light-years from Earth, appearing in the constellation Centaurus. Its brightness makes it the fifth-brightest galaxy in the sky.

Image credit: ESO/WFI (Optical); MPIfR/ESO/APEX/A.Weiss et al. (Submillimetre); NASA/CXC/CfA/R.Kraft et al. (X-ray)

Backyard Astronomy: September 2015

Here are some fun astronomical events you and your family can enjoy in the month of September. All you need is an inexpensive telescope or binoculars for most of these events, but some of them are viewable with the naked eye.

September 4: Mercury at Greatest Eastern Elongation. What this means in plain language is that Mercury will be at its greatest apparent distance (27 degrees) from the Sun in the sky. It’s a great time to observe Mercury, because it’ll be highest in the sky in the evening, just after sunset.

September 23: September Equinox. During an equinox, the Sun shines directly onto the equator, so there is an equal amount of day and night everywhere in the world. This marks the first day of fall in the Northern Hemisphere (Autumnal Equinox), and the first day of spring in the Southern Hemisphere (Vernal Equinox).

September 27-28: Total Lunar Eclipse. A total lunar eclipse occurs when the Earth moves between the Sun and the Moon (see below). Unlike a solar eclipse, in which the Moon moves between the Sun and the Earth, you don’t need any protective eyewear to watch a lunar eclipse. During the eclipse, the Moon will gradually get darker, ultimately turning red in color. The lunar eclipse will be visible from the Americas, Europe, Africa, and parts of Asia. See here to determine visibility and times in your part of the world.


Weekly Psalm 19: M74

Here is your weekly reminder of Psalm 19 — galaxy M74.

Galaxy M74 is a perfect example of what’s called a grand design spiral galaxy, and it’s one of my all-time favorites. M74 appears face-on from our position on Earth, allowing us to see its symmetrical arms spiral gracefully out of its center. Note the blue clusters of star formation and glowing pink pockets of excited hydrogen gas. The dark swirls are dust lanes that obscure starlight, much the way dust in the Earth’s atmosphere blocks sunlight. M74 (the 74th object in the Messier catalog) is about 32 million light-years from Earth and appears in the constellation Pisces.

Image of M74 credit:NASA, ESA, and the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration.

Weekly Psalm 19: Mars

Here is your weekly reminder of Psalm 19 — Mars.


This image shows Mars from 2500 km above its surface. The great slash covering more than half of Mars’ apparent diameter is Valles Marineris (Mariner Valley), named after its discoverer, the Mariner 9 orbiter that visited the Red Planet in the early 1970s. Valles Marineris dwarfs the Grand Canyon — it is 4,000 km long, 200 km wide, and in some parts it is 7 km deep. To put this into perspective, consider that the distance from Seattle to New York is 4,600 km.

Why do we love Mars so much? I think it’s because for two centuries Mars offered the most tantalizing possibility of extraterrestrial life in the universe. It started in the 18th century when William Herschel was moved by similarities between the Red Planet and Earth to speculate that it may be inhabited, and was further fueled a century later by Giovanni Schiaparelli’s observations of what he thought were canals on its surface.

We’ve observed Mars in much greater detail through several NASA missions, including landers, and have found no compelling evidence that is now or has ever been inhabited. Yet that hardly seems to matter. Perhaps it is because Mars offers a challenge that’s tantalizingly within reach — to visit the planet and perhaps even colonize it — that we remain so fascinated with our nearest planetary neighbor.

Image credit:NASA/JPL-Caltech.

Weekly Psalm 19: The Horsehead Nebula

Here is your weekly reminder of Psalm 19 — the Horsehead Nebula.

The Horsehead is one of the best-known nebulae, owing to its distinctive shape in the likeness of — you guessed it — a horse’s head. This is one small part of a region of ongoing star formation in the great Orion Molecular Cloud Complex. The pink color in the cloud is a result of hydrogen gas excited by the ultraviolet light from a nearby star.

Most images of the Horsehead Nebula show it in visible light; the above image is in infrared, which allows us to peer into the inner structure of the cloud. Visible light is blocked by dusty gas, but longer wavelength infrared light can penetrate the dust.

Image credit:NASA/ESA/Hubble Heritage Team.

Weekly Psalm 19: Saturn’s Rings and Titan

Here is your weekly reminder of Psalm 19 — Saturn’s Rings and Titan.

At least I think it’s Titan. It’s one of Saturn’s moons, anyway. This image was taken by the Cassini spacecraft as it orbited Saturn. The spacecraft is named after the 17th century Italian astronomer, Giovanni Cassini, who studied Saturn extensively.

Here you can see the outer rings of Saturn, including the Cassini Division (the large division between the rings) and the Encke Gap (the smaller gap between the outermost rings). The rings are made of icy and rocky particles that range in size from a thousandth of a millimeter (about the size of smoke particles) up to a meter. It is not known for certain how the rings were formed. One hypothesis is that a moon of Saturn was either ripped apart by Saturn’s gravity or smashed by an asteroid, and the debris formed the rings; another is that the rings are made of leftover material from the formation of the solar system.

Image of Saturn and Titan, credit: Cassini Imaging Team, SSI, JPL, ESA, NASA.