In the Universe: Is Earth Alone in Having a Total Solar Eclipse?
As inhabitants of our earth, we may be mesmerized by the eclipses that we view and yet we have come to accept them as part of our planetary experience. Throughout the millennia, mankind has placed a value on the reason and purpose of eclipses, but it has only been in the last few hundred years that we realize the complex conditions that are required for a total solar eclipse.
A simple definition simple of this event is: “Total solar eclipses occur when the New Moon comes between the Sun and Earth and casts the darkest part of its shadow, the umbra, on Earth. The darkest part of the eclipse, the totality, is almost as dark as night.”
When we drill down into the requirements that are needed for a total solar eclipse, we find that it is a combination of location, distance, and size of the planet, sun and satellite/moon. This planetary ‘harmonic balance’ requires that the location and distance of the earth, moon, and sun be very specific and the comparable sizes of each be perfectly matched by percentages.
The details about our place in our solar system and the finely choreographed dance that we perform with our Moon includes:
*The average distance between Earth and Moon is approximately 30 times Earth's diameter.
*The Sun is 400 times the Moon's diameter, and 400 times as far away. That coincidence means the Sun and Moon appear to be the same size when viewed from Earth. A total solar eclipse, in which the Moon is between the Earth and Sun, blocks the bright light from the Sun's photosphere, allowing us to see the faint glow from the corona, the Sun's outer atmosphere.
*The Moon has approximately 1/4 Earth's diameter, 1/50 Earth's volume, and 1/80 Earth's mass. Earth is very dense overall (it is the densest planet in the Solar System), but the Moon is light for its size.
This ‘math’ explains why we can view both the sun and the moon and they visually appear to be the same size. It is these critical pieces that may place us in a unique situation that allows all types of eclipses to occur, with the rarest being a total solar eclipse.
Our Own Solar System
To address the question as to whether other planets in the universe have total solar eclipses we need, to begin with, our own solar system. While we may share our rotation around our sun with other planets, and many do have satellites/moons, it seems that Earth is the only one that has the geometrical circumstances that allow us a total solar eclipse.
In a Guide to the Universe article, they state: “This phenomenon is certainly unique in our solar system. Mercury and Venus don't possess any moons, the two orbiting Mars are far too tiny, those around the gas and liquid giants, Jupiter, Saturn, Uranus and Neptune, while pretty huge, are easily dwarfed by their host planet.”
There are 5 satellites in our solar system that are capable of completely occulting the Sun: Amalthea, Io, Europa, Ganymede and Callisto.
What Have We Discovered in the Milky Way?
Our search for Earth 2.0 has taken us on an incredible path. While locating a planet close to ours in the ‘Goldilocks or temperate Zone’ isn’t a requirement for the ability to have a total solar eclipse, this was a priority for us to see if Earth is indeed common or unique. Scientists have found a number of solar systems that have reset their initial ideas of how our galaxy and possibly the universe came about. Looking for Earth 2.0 was a place to start.
Examining our Milky Way galaxy with its one hundred billion planets has given us a perspective for the rest of the universe. In an NASA.gov article they state:
“A six-year search that surveyed millions of stars using the microlensing technique concluded that planets around stars are the rule rather than the exception. The average number of planets per star is greater than one. This means that there is likely to be a minimum of 1,500 planets within just 50 light-years of Earth.
The results are based on observations taken over six years by the PLANET (Probing Lensing Anomalies NETwork) collaboration, which was founded in 1995. The study concludes that there are far more Earth-sized planets than bloated Jupiter-sized worlds. This is based on calibrating a planetary mass function that shows the number of planets increases for lower mass worlds. A rough estimate from this survey would point to the existence of more than 10 billion terrestrial planets across our galaxy.”
Most recently, scientists have discovered the Trappist-1 solar system that is just thirty-nine light years from earth. This solar system has seven planets that are tightly locked in their orbit around an ultra-cool dwarf star and each one is within the temperate zone. But there is one problem, many of the planets have only one side that faces the sun. But the fact that each of these seven planets is close to the size of Earth offers a glimmer of hope that they may contain our idea of the requirements needed to harbor life, but could potentially imitate Earth in other ways, including the ability for eclipses.
Given that our Milky Way Galaxy is over one hundred billion light years across, this recent discovery of Trappist-1 means that we have a very good potential that could be considered a ‘next door neighbor’. It is thus far unknown if any of these planets have satellites/moons and we will have to continue our explorations with higher powered telescope technologies to pursue that answer.
Extrapolating to the Universe
Planetary scientists are on a continual study of how solar systems develop. In the last number of years, we have developed theories that the path of planets alters during creation, often moving from the outer edges to the closer proximity of their sun. We have realized that the setup of our own solar system, with smaller planets inside and larger planets at the edge, is not necessarily a baseline example of how others exist; and have made major adjustments as we see some solar systems with large planetary giants orbiting close to their sun.
The mere fact that we have been able to locate the Trappist-1 solar system so close to us and that it contains so many planets that are ‘earth-like’ offers hope that there are millions or potentially billions of planets similar to earth that could have not just a single moon, but multiple moons offering a variety of eclipse types.
Resources & More Information
For answers to 76 Frequently Asked Questions on this Solar Eclipse, Click HERE for FAQ
For Google Map of the PATH of TOTALITY across the USA, Click HERE for Solar Eclipse MAP
For State by State Information on this Solar Eclipse, Click HERE for INFO
For T-shirts, mugs, pillows, tote bags to celebrate, to commemorate, Click HERE for GEAR