habitable zone Archives - DOES GOD EXIST? TODAY

July 8, 2024July 7, 2024

Just Right for Life to Exist

Since astronomers have discovered more than 5,000 exoplanets orbiting stars other than our Sun, many insist there must be life elsewhere in the cosmos. For those of us who believe in God, that isn’t really an issue. If there is life out there, God created it, but the Bible only speaks to our planet. However, the evidence is growing that our planet is more unique than most people realize. A “Goldilocks” planet is at the proper distance from its star so that the temperature is “just right” for liquid water to exist on the surface. Some exoplanets appear to be in the habitable zones of their stars, but many other factors must also be just right for life to exist there.

Most known exoplanets are like Jupiter, having no terrestrial surface. To support life, a planet must be the right size, have a stable orbit inside the habitable zone of a stable star, and have the right atmosphere. It must also have working plate tectonics and a large moon to maintain a stable axis tilt. To be just right for life to exist, a planet must also be in the habitable zone of its galaxy – not near the center, exposing it to lethal gamma-ray bursts.

Our Sun is a G spectral star, but only 9% of the stars in our galaxy are that type. M-class dwarf stars are the most common and long-lived stars, but they emit large amounts of radiation that would cook any life on their planets. Also, planets around such a star would become tidal-locked, with one side facing the star being excessively hot while the other remains cold.

Another star system requirement for life would be having outer planets large enough and in the correct position to sweep away asteroids and comets that would bombard an inner planet. To support life, a planet also needs a strong magnetic field to shield the surface from the star’s radiation and cosmic rays.

Our Earth is just right for life to exist. We are defining life as the biology books do: being able to move, breathe, respond to outside stimuli, and reproduce. Any conjecture about fire people or rock people is in science fiction – not scientific fact. The bottom line is that Earth is a special place created by God for a special purpose and is unique among all other objects in the cosmos.

Reference: “Is Earth the Only Goldilocks Panet?” in Discover magazine, July/August 2024, pages 54 -57.

June 19, 2023June 18, 2023

The Cosmological Argument for God

Cosmology provides strong evidence for God’s existence. The basic cosmological argument for God involves three simple questions:

1) Was there a beginning to time, space, and matter/energy? The evidence says there was.

2) Was the beginning caused or uncaused? Taking the position it was uncaused violates scientific conservation laws.

3) If it was caused, what or who was the causer? The evidence is that the cause can not be blind, mechanistic chance. Logic suggests that the cause was an intelligence, in other words, God.

As more data becomes available to support intelligence as the cause of planet Earth, the cosmological argument for God becomes stronger. If we define life as that which can breathe, move, respond to outside stimuli, and reproduce, what is necessary for life to exist? Astronomers now talk about the habitable zone (HZ) of stars. This is the zone around stars where the temperature on a planet would allow water to exist in the liquid state on the surface.

Recent discoveries have shown that M-class dwarf stars are the most common and longest-lived stars. The problem with these stars is that their HZ is very close to the star, so tidal forces would lock the rotation of any planet so its same side would always face the parent star. One side of the planet would be constantly hot while the other would be cold. Also, M-class stars would bombard these planets with stellar flares causing massive radiation levels that would eliminate any possibility of life. Other star types create various problems for a life-supporting planet.

Astronomers have determined there is a galactic habitable zone (GHZ) in addition to the star’s habitable zone. A star must be far from the galactic center to have a planet with life on it. The high star density near the core of a galaxy exposes the star system to deadly supernovae and gamma-ray bursts. Mass distribution within a galaxy is also an issue because, near the galaxy’s core, mass concentrations cause gravitational instability.

The basic cosmological argument for God is now supported by a vast number of parameters that must be within precise limits to allow life to exist in a planetary system. Having a large moon is essential to the survival of life on a planet. Likewise, having a shield against incoming cosmic bodies is critical. A body the size of Comet Hale Bopp hitting planet Earth would have sterilized it, killing even microbes that might be present. The Earth’s shield is the arrangement of the Jovian planets. Jupiter, Saturn, Uranus, and Neptune preventing objects like Hale Bopp from reaching Earth.

The more we look at the cosmos, the unique qualities of our planet reinforce the cosmological argument for God. Proverbs 8 personifies Wisdom speaking of God’s creative power and design. As we learn more about the cosmos, the stronger the evidence becomes that “in the beginning God created the heavens and the earth” (Genesis 1:1).

Reference: “Is Earth the Only Goldilocks Planet?” by Klaus R. Brasch in Astronomy Magazine for July 2023, pages 18-23.

February 6, 2023February 5, 2023

The Uniqueness of Planet Earth

One of the positive things about science is that its methodology allows change. When new data become available, theories are either supported or discarded, resulting in the constant evolution of what scientists believe to be true. This applies to our understanding of the uniqueness of planet Earth.

Experts from NASA’s Goddard Space Flight Centre have announced that a widespread assumption about life on other planets is not valid. Science has assumed that other stars similar to our Sun in size and type also have similar stability. The Sun has not changed significantly in brightness and temperature in the hundreds of years that scientists have been observing and measuring it. Recent measurements of similar stars show that three-quarters of them go through changes in both brightness and temperature.

Dr. Noah Tuchow of NASA says that the number of alien worlds that could contain life has been “vastly overestimated.” The planetary zone where water could exist as a liquid is known as the “Goldilocks Zone.” A planet would have to be orbiting a star with relatively constant heat output to be in such a zone. Planets that formed too close to be in the star’s habitable zone would have their water boiled away. Those that began beyond the habitable zone would have frozen water that would take a long time to melt. Either way, they would have a relatively short time to support life. This shows the uniqueness of planet Earth.

NASA has created a new label for planets that enter the habitable zone after their formation due to orbiting a changing star. They call it the “Belatedly Habitable Zone” (BHZ). Dr. Tuchow says, “A planet’s history dictates its current potential to host habitable conditions and life.”

Our point is the uniqueness of planet Earth, not whether it is the only place where life exists. However, if life exists elsewhere, God created it. Every discovery scientists make shows that Earth is an extraordinary place and our Sun is an exceptional star. Considering what we have learned about the cosmos, the statement of Psalms 19:1 is more meaningful today than when it was written thousands of years ago: “The heavens declare the glory of God, and the sky shows His handiwork. Day to day they utter speech, and night to night they show knowledge.”

Please go to our doesgodexist.org website to see a chart titled “Evidence for Design in the Universe,” listing 47 of the vast number of variables required for a life-sustaining planet. The constancy of the parent’s star adds one more limiting variable to what it takes to have a world able to support life.

References: ARXIV and MSN.com

March 8, 2021March 7, 2021

Factors Required to Support Life

The media often brings news about newly-discovered planets in the “habitable zone” of some star beyond our solar system. They usually mean that scientists think the planet may be the right distance from the right kind and size of star for water to exist in liquid form.
Calling such a planet “habitable” may be misleading because there are many factors required to support life.

One of those factors is that the star also has to be extremely stable, as our Sun is. Consider the fact that a change in the Sun’s luminosity of only two percent would make Earth uninhabitable. That seems hard to believe, but scientists have calculated and modeled it.

If the Sun were only two percent dimmer and everything else the same, there would be more snowfall. Because snow reflects more of the Sun’s heat than land or water does, Earth’s surface would become cooler. The cooling would cause more snowfall, resulting in more reflection of the Sun’s rays and, therefore, more cooling. The result would be a runaway freezing of the surface water, and the entire Earth would become covered with ice and snow.

On the other hand, a two percent increase in the Sun’s brightness would cause greater evaporation of Earth’s surface water. The resulting water vapor would act as a greenhouse gas, trapping more of the Sun’s heat in the atmosphere. The increased heat would cause more evaporation resulting in more water vapor and an increased greenhouse effect. The result would be global warming on a massive scale.

Either way, life on Earth would not be possible. We don’t know if there are any other planets in the universe with all the factors required to support life. Our finely-tuned Sun is only one of many features that allow life on this planet. Some people would suggest that our just-right Sun is merely an accident, but we think this is another case of design by a wise Creator.

February 1, 2020January 31, 2020

Stars and Habitable Zones

The more scientists study Earth and other objects that surround us in space, the more variables we realize must be carefully controlled for life to exist. Many times before, in our posts, our videos, our books, and our printed quarterly, we have discussed the growing list of parameters that must be carefully chosen. NASA posted a graphic of different kinds of stars in the cosmos and whether they could support life. This picture of stars and habitable zones adds to our understanding of the unique qualities of our Sun.

Water is essential for life. Science defines life as having properties such as moving, breathing, eating, reproducing, and responding to outside stimuli. We don’t discuss “rock people” or “gas people” because they don’t fit that definition. For that reason, scientists are interested in stars and habitable zones–the just-right “Goldilocks zone” surrounding a star where water can exist as a liquid.

In their daily posting on apod.nasa.gov for January 31, 2020, NASA gives the distribution of Goldilocks zones for G spectral stars like our Sun, which are yellow, K dwarf stars, which are orange, and M stars, which are red. The other spectral groupings, such as blue stars, are not considered because of their high radiation levels and activity, which would make life impossible.

The most common type of star in our galaxy, making up 73% of all stars in the Milky Way, are M stars. These red stars have very active magnetic fields and massive radiation. Their Goldilocks zone would be minimal and very close to the star. Orange K stars make up 13% of the stars in the Milky Way. They have a modest Goldilocks zone but are fairly active with some radiation levels. Yellow G type stars like our Sun, make up only 6% of the stars in the Milky Way. These stars have very large Goldilocks zones, and they are very quiet compared to K stars.

As we consider stars and habitable zones, we must realize that the type of star is just the beginning of the variables necessary for a star system to support life. Other critical factors include the size of the star, the location of the planet relative to the star, and the shielding a planet has for protection from the radiation of the star. Also, the stability of the star’s location in the Milky Way is another factor that goes into a life-supporting planetary system.

Our existence is not a product of chance. The more we learn about the Earth, the Sun, and the stars and habitable zones within the Milky Way, the more we understand that the statement, “In the beginning, God created the heaven and the earth” is a massive understatement of what God did to make a place for us to exist.

May 26, 2019May 24, 2019

How Far Away Is the Sun?

How Far Away Is the Sun? Does it matter how far away the Sun is? Absolutely yes. The picture shows the order of the planets in our solar system, but not their distance from the Sun. So how far away is the Sun from Earth?

Any star that has planets orbiting it may potentially create a “habitable zone” where the light and heat are just right for the possibility of life to exist. Earth resides in the middle of the Sun’s habitable zone with Venus and Mars near the edge of the zone. Of course, there are many other factors required to support any kind of life, and it appears that Earth is the only planet in our solar system that has all of those factors. Earth has everything needed to support not just primitive life, but advanced life.

So what is the range of the habitable zone? That depends on the star. The size and brightness of the star are critical. Another essential factor is the type of radiation emitted by the star. Our Sun has the just-right radiation. Other stars may emit x-rays, gamma rays, or other deadly radiation in amounts that would destroy all life and prevent a habitable zone from existing.

Back in the eighteenth century, scientists determined the distance to the Sun by watching a transit of Venus across the Sun. Venus passes between the Earth and the Sun twice every hundred years or so. By measuring the time of the transit of Venus from two locations on Earth, scientists were able to use triangulation and simple math to calculate the distance to the Sun.

But the question was, how far away is the Sun? The Sun is about 93,000,000 miles (150,000,000 km) away from us. Since the speed of light is 186,000 miles (300,000 km) per second, it takes about eight and one-third minutes for the light from the Sun to reach the surface of the Earth. The energy the Sun delivers to our planet is just right to make life possible.

If someone asks you “how far away is the Sun,” you can say it is the “just right” distance. There are so many “just right” features of our planet that we can genuinely say we are in the “Goldilocks Zone.” Some think it was all just an accident, but we believe it was God’s plan and design.
— Roland Earnst © 2019

December 26, 2018December 24, 2018

Galactic Coincidences?

On a clear, moonless night, you can look up and see the Milky Way. Actually, we are in the Milky Way, a spiral galaxy of 200 billion stars one of which is our Sun. We are located in a spiral arm of that galaxy 26,000 light-years from its center. Our location seems to indicate many galactic coincidences.

At the center of the Milky Way (and perhaps all galaxies), there’s a black hole sending out lethal radiation to a distance of 20,000 light-years. Farther out than 26,000 light-years from the center, heavy elements that are vital to our existence and survival are scarce. We are in what astronomers call the “galactic habitable zone.”

Spiral galaxies rotate, and we are near the co-rotation spot where our solar system moves at almost the same rate as the spiral arm we are in. If we were in precisely the co-rotation spot, we would experience gravitational “kicks” which could send us out of the habitable zone. If we were far away from the co-rotation spot, we would fall out of the arm and be subjected to deadly radiation.

In the vast majority of spiral galaxies, the habitable zone and co-rotation spot do not overlap. Most other spiral galaxies are not as stable as ours. Most galaxies are not spiral galaxies and would not have a stable location for advanced life.

Furthermore, galaxies exist in clusters, and our cluster called the “Local Group” has fewer, smaller, and more spread-out galaxies than nearly all other clusters. Most galaxies are in dense clusters with giant or supergiant galaxies which create deadly radiation and gravitational distortion making advanced life impossible.

These are only a few of the many factors that “just happen to be” true of the place where we live. Are these just galactic coincidences? Some say it’s all accidental. We say it’s a grand design by a Master Designer. The next time you look up at the Milky Way, thank God that we are precisely where we are.
–Roland Earnst © 2018

October 3, 2018May 22, 2021

Alone In the Milky Way

Yesterday we mentioned an article by John Gribbin in Scientific American (September 2018, page 96 or online HERE.) The title of the article was “Are Humans Alone in the Milky Way?” Although Gribbin suggests that some form of life exists elsewhere in the galaxy, he insists there could be no sentient beings like ourselves. The reasons for concluding that we are alone in the Milky Way galaxy are these “amazing” and “implausible” “coincidences.”

SPECIAL TIMING. The elements that make up a terrestrial planet like Earth are produced from hydrogen and helium by thermonuclear fusion. We see supernova explosions producing the heavy metals that make up a terrestrial planet and life itself, but it takes time for this process to create the necessary elements. Most of the exoplanets we see have minimal amounts of the heavy elements because they are early in their stellar evolution. Even the sun itself is 71% hydrogen and 27% helium with only 2% metals. The timing of putting the materials together to make a terrestrial planet is critical.

LOCATION IN THE GALAXY. The location of a solar system in the galaxy makes a difference. The galactic habitable zone is the area where there is a freedom from the concentration of supernovae. Systems near the center of the galaxy have high levels of radiation in the form of X-rays and cosmic rays. There is a massive black hole in the center of our galaxy called Sagittarius A which produces massive amounts of radiation. Gamma-ray bursts occur in certain places in the galaxy. In our area of the galaxy, sterilizing radiation bursts do not happen.

Recent studies of the galactic habitable zone tell us that it extends from 23,000 to 30,000 light-years from the center or only about 7% of the galactic radius. This zone contains only about 5% of the stars, because stars tend to concentrate toward the core of the galaxy. Our Sun is close to the center of the galactic habitable zone providing rare long-term stability.

TYPE OF PLANET. So far astronomers have discovered about 50 “earth-like planets.” What that means is that they have found rocky planets in the habitable zone that are about the same size as Earth. Venus would qualify as an “Earth-like planet,” but it is an excellent example of how misleading that statement is. Venus has a thick crust with no sign of plate tectonics, no magnetic field, no way to recycle materials, and no stabilizing moon. Our Moon keeps the tilt of Earth’s axis at 23 ½ degrees providing a stable climate.

Realize that all of these factors are just to have a ball of rock in the right place at the right time with the right materials with which to make life. Now we would need to calculate the odds of getting the right chemicals together at the right time in the right place with the right catalyst to make the first living thing. Books have been written about how improbable those steps are. The writers are not religious fanatics, but scientists who are doing the research.

The Scientific American article, concludes that we are alone in the Milky Way:

“As we put everything together, what can we say? Is life likely to exist elsewhere in the galaxy? Almost certainly yes, given the speed with which it appeared on Earth. Is another technological civilization likely to exist today? Almost certainly no, given the chain of circumstances that led to our existence. These considerations suggest we are unique not just on our planet but in the whole Milky Way. And if our planet is so special, it becomes all the more important to preserve this unique world for ourselves, our descendants and the many creatures that call Earth home.”

We must make one additional point. If an intelligent Creator was involved in this process, the probability of a habitable Earth with life on it is 100%. Perhaps we are not really alone in the Milky Way because there is a God who cares about us. For those who might want to consider this option, we encourage you to watch program #6 of the video series available free on doesgodexist.tv.
–John N. Clayton © 2018

August 8, 2017October 5, 2018

M Dwarf Exoplanets

Imagined M Dwarf Exoplanets
One of the interesting scientific discoveries of the past decade has been that there are planets orbiting other stars (called exoplanets) and that many of these planets may have temperatures that would allow liquid water to exist on their surfaces. There has been a special interest in M dwarf exoplanets.

In theory, all stars could have a possible planet in a zone where the temperatures would be between zero and 100 degrees Celcius. However, that zone could be very small, and there are many factors required to make life possible, and many that would make life impossible. In an article in Science News dated June 24, 2017, (page 18) some of those factors were mentioned. They include stellar flares, gravitational locking, and especially the life expectancy of the star.

Stars age and the period during which their habitable zone could exist in a stable form is very short. M dwarf stars are held up as having long enough lifetimes for water to exist and biological processes to take place. Since they are the most common type of star in the Milky Way (70% of all the stars in our galaxy) scientists are studying them closely. We have reported before on one of them called TRAPPIST-1.

As more data comes in, it is becoming apparent that although M dwarf exoplanets remain as they are for very long times, they are still not stable enough to sustain life. Scientists hoping to find another “earth” orbiting another star are learning that M dwarfs are not good candidates even though they have some of the conditions necessary for life.

As we have said before, if God wanted to, He could create life elsewhere in the universe. However, the special nature of Earth continues to be more apparent the more we learn. As we learn more about the universe, we see more clearly that “the heavens declare the glory of God and the firmament shows His handiwork” (Psalms 19:1).
–John N. Clayton © 2017

March 16, 2017October 6, 2018

Exoplanet Data Goes Wild

An exoplanet is a planet orbiting a star other than our Sun. At the time that I am writing there are 3,565 known exoplanets, but by the time you read this, there could be over 4,000. In spite of what the media says, there have been no “Earth-twin,” “habitable,” or “Earth-like” planets found. These are cliches the media throws around which have very little scientific validity. When a scientist identifies a planet as being in a habitable zone, it simply means that water could exist on the planet in a liquid form. Scientists consider water, carbon, and oxygen essential for life. But there are many other variables that must be carefully chosen before an “Earth-like” planet could actually have life on it.

The exoplanets that have been discovered so far are an incredibly varied group. Most are too big, too hot, too gassy (like our gas giant Jupiter), or they have orbits that are too eccentric (ovals, not circles) to support life. Some planets are so hot that they rain glass. Others are so cold that no biological organism could exist on them. The stars around which these planets orbit are also an incredibly varied group with enormous ranges in size, activity, temperature, and radiation levels. In most cases, those stars are orbiting other stars making life nearly impossible.

Every day new discoveries are reported. We now understand more about how planets form, and that tells us how special our planet is. We need to take care of it, because moving to another planet is not feasible now, and may never be possible. Data from Discover magazine, April 2017, pages 40 -45.
–John N. Clayton © 2017