NASA has made an announcement of finding the first "earth-like" planet in the middle of the star's habitable zone through the Kepler satellite, which finds planets through stellar dimming during transits. To date (2011), over 700 extrasolar planets have been confirmed to exist, although Kepler has a potential list of over 2,000 more. The current announcement probably had the widest news coverage of any recent NASA statement. This page examines the claims, along with distortions by the media, and NASA artists themselves.
Stars and planets are given names according to the following convention. A star's name usually includes some numbers identifying it. The planets being discovered by the Kepler mission are being numbered sequentially by discovery. Stars are labeled with the number followed by the letter "a." So, the "name" of the star around which the new earth-like planet is revolving is designated as Kepler 22a.1 Planets are numbered with subsequent letters, beginning with "b." So, the newly discovered planet is designated as Kepler 22b. Unlike the last announcement of the last "earth-like planet," Gliese 581g, within its small star's habitable zone, this one is orbiting a near solar-twin. Small stars, like Gliese 581a, exhibit lower energy spectral emissions, which are not conducive as strong supporters of photosynthesis. In addition, their weak emissions require planets to be located very close to the parent star to be within the habitable zone, resulting in tidal locking (one side of the planet always faces the star). Stars larger than the Sun burn much more quickly, with rapid escalation of stellar luminosity, which continually moves the habitable zone further and further away from the star. So, realistically, only stars that are nearly solar twins would be conducive to harboring life. Kepler 22a happens to be such a star, which is why scientists were so excited to find a rocky planet orbiting around it.
NASA's definition of the habitable zone is very generous. For example, using our own solar system, they say that Venus and Mars are both within the habitable zone. However, according to the inverse square law, the solar irradiance received by Venus should be nearly twice that of earth. Even with Earth's relatively thin atmosphere, it would be uninhabitable, due to overheating, if located as close as the orbit of Venus. However, since Venus has a thick greenhouse atmosphere, surface temperatures are in excess of 460°C—even higher than Mercury, the closest planet to the Sun. If the earth were located toward the outer limits of the Sun's habitable zone, beyond the orbit of Mars, it would a frozen ball of ice. Planet Kepler 22b is located near the inner part of Kepler 22a's habitable zone, so it's likely to be much warmer than the claimed 72°F in news stories.2
Planet Kepler 22b
Although declared to be "earth-like," Kepler 22b is actually 2.4 times more massive than earth. This increased mass likely impacts the atmospheric content of the planet. Planets must possess a minimal mass in order to retain an atmosphere. For example, Mars has only 10% the mass of the earth, and almost no atmosphere. Extensive evidence indicates that it once had a thicker atmosphere and large bodies of water on its surface. However, because of its reduced gravity, it lost nearly all of that atmosphere and water due to the actions of the solar wind. The earth originally had a much denser atmosphere that was mostly blasted into space during the collision that formed the Moon. Had it not been for this fortuitous collision, the earth would have had an atmosphere similar to Venus (81% the mass of the earth), which has an atmosphere 80 times denser than earth's. NASA scientists have assumed that Kepler 22b has an atmosphere similar to earth's. This assumption is almost certainly wrong, unless the planet experienced a large collision event, similar to earth's, early in its history. With at least 2.5 times the mass of earth, the planet would likely have an atmosphere much denser than Venus, making life there extremely unlikely. Such a dense atmosphere would contribute to a large greenhouse effect, which would raise temperatures dramatically. If Kepler 22b ever had water, it probably doesn't now, having been evaporated and blown away by Kepler 22a's solar wind. The artist's impression (right) is almost certainly wrong, since even NASA scientists admitted in their December 20, 2011 news conference that Kepler 22b most likely has a very dense atmosphere compared to earth (not the thin, wispy clouds we see in the diagram).
The newly confirmed planet Keppler 22b has been advertised as being an earth-sized planet within the habitable zone of its star, with an average temperature of 72F. What the new media does not tell you is that the temperature assumptions are based upon the planet having an atmosphere identical to earth's. The assumption is extremely unlikely. First, the earth's atmosphere is very thin for the size of planet, having achieved such a thin atmosphere due to the collision that formed earth's moon. Since Kelper 22b is 2.4 times more massive than earth, it most likely has an atmosphere as dense or denser than Venus. With such a thick atmosphere, any water on the planet would be in the form of superheated steam or boiled off completely. I wouldn't plan on moving there any time soon. If you do, remember to take lots of sunblock!
- Does 'Goldilocks' Planet Gliese 581g Harbor Life?
- The Incredible Design of the Earth and Our Solar System
- Moons Like Earth's Moon are Rare in the Universe
- God of the Gaps - Do All Christian Apologetics Fall Into This Kind of Argument?
Rare Earth: Why Complex Life is Uncommon in the Universe by Peter D. Ward and Donald Brownlee
A secular book that recognizes the improbable design of the earth. Paleontologist Peter D. Ward and astrobiologist Donald Brownlee examine the unusual characteristics of our galaxy, solar system, star, and Earth and conclude that ET may have no home to go to. Surprisingly, the authors conclude that the amazing "coincidences" are the result of good luck and chance.
A classic book for modern Christian apologetics and science, recently updated with fully one third of the book updated. Dr. Ross presents the latest scientific evidence for intelligent design of our world and an easy to understand introduction to modern cosmology. This is a great book to give agnostics, who have an interest in cosmology and astronomy.
- NASA's Kepler Mission Confirms Its First Planet in Habitable Zone of Sun-like Star. Kepler Mission News, December 5, 2011.
- On newly discovered Earth-like planet, it's 72 degrees. Florida Today, December 6, 2011.
- Leslie Mullen. 2010. Doubt cast on existence of possibly habitable alien planet, Astrobiology Magazine.
Today's New Reason to Believe
Integrating Science and Faith
- 02/11/2016 07:46 AM
A Periodic Table for Protein Structures Reveals Biochemical Design
During my senior year in high school, I was the proud winner of the Periodic Table Competition at the West …
- 02/08/2016 06:09 AM
Phosphorus No Help for Chemical Evolution
Born under a bad sign Been down since I began to crawl If it wasn’t for bad luck You know, …
- 02/04/2016 06:00 AM
How God Used Short-Lived Radioisotopes to Create Life
Have you thanked God for short-lived radioisotopes today? You should. Because our solar system was exposed to a huge abundance …
- 02/01/2016 06:06 AM
Recent Research Strengthens the Creation-Friendly Grand Tack Model
Last month I wrote an article describing how the Grand Tack model explains the orbital configurations of all eight planets …
- 01/28/2016 08:38 AM
The Lab: Preparing a New Generation of Leaders in Science
Have you ever noticed how much energy Christians invest in “responding to” things? We respond to movies, books, politics, current …
- 01/25/2016 06:22 AM
Answering FAQs on Vaccine Safety
My previous article titled “Vaccine Safety and Loving Our Neighbors” generated some ardent reader responses. In this follow-up article I …
- 01/21/2016 07:06 AM
Did Mars Ever Have Liquid Water?
In recent years, the question of Mars has shifted from whether it hosts advanced life (an idea shown to be …
- 01/18/2016 06:00 AM
Is the Peer Review Process Advancing Science?
In today’s society, we often look to science as an unbiased source of truth, regulated by the peer review process. …
- 01/14/2016 06:00 AM
How Face Mites Support the Biblical Account of Human Origins
It’s a little gross to consider, but every one of us has mites that live in our hair follicles. Most …
- 01/11/2016 02:26 AM
Mites Take a Bite Out of Evolution
The week between Christmas and New Year’s Day holds special significance for our family. It is the time of the …
Last updated December 21, 2011