Exoplanets

Alien Civilizations and the Fermi Paradox

This is a submission for Kevin’s No Theme Thursday

Kevin’s artistic picture above makes me think of Alien Civilizations. Do they exist? Do they exist in our Galaxy? To quote Enrico Fermi, if they do exist “Where is Everybody?”. That is the famous Fermi Paradox.

A telescope and a background showing the milky way — Did we find an advanced civilization in our Galaxy, which has hundreds of billions of stars?

We have found thousands of exoplanets, and it is estimated that there are 11 billion potentially habitable Earth-sized planets orbiting stars roughly the same size as the sun in the Milky Way. It is estimated that there are an additional 40 billion potentially habitable Earth-sized planets orbiting red dwarf stars in the Milky Way. Earth is an estimated 4.5 billion years old whilst our Milky Way Galaxy is an estimated to be 13.6 billion years old. Add that there are at least hundreds of billions of Galaxies like the Milky Way in the observable Universe. Yet, human astronomers have not detected any signs of alien civilizations, and there is no evidence Earth has been visited by aliens in the past.

A picture of the Andromeda Galaxy with a bright white light near its center. The bright light is almost outshining the entire galaxy | Alien Civilizations and the Fermi Paradox — It should be noted that even though our Galaxy is 13.6 billion years old, its beginnings were very violent with a lot of supernova explosions, which were necessary for higher elements to come into existence and making life possible. So, we need to count out the first couple of billions of years. This is a supernova explosion in the center of the Andromeda galaxy “Elements of this image furnished by NASA” It is essentially an enhanced photo of a supernova explosion in a neighboring galaxy. Stock Photo ID: 2495486227 by muratart.

Blue and brown Earth like planet with rings. — Exoplanets, we found thousands but there are likely many billion habitable exoplanets in our Galaxy. This is an imagined Earth like exoplanet. Stock Illustration ID: 1440413666 by Dotted Yeti.

A planet surrounded by rings that are hundreds of times wider than the planet | Alien Civilizations and the Fermi Paradox — This is an illustration of a real exoplanet that we’ve found. J1407b is an exoplanet 20 times more massive than Saturn. It has enormous rings and is often referred to as Super Saturn. It may not harbor life. Stock Illustration ID: 2329821675 by Love Employee.

In this context, I would like to mention the Drake equation. The Drake equation is a probabilistic equation used to estimate the number of communicative extraterrestrial civilizations in the Milky Way Galaxy. It was created in 1961 by American astrophysicist and astrobiologist Frank Drake. This is the equation N = R * Fp * Ne * Fl * Fi * Fc * L. where N is the number of civilizations in the Milky Way galaxy with which communication might be possible.

R = the average rate of star formation in our galaxy.
Fp = the fraction of those stars that have planets.
Ne = the average number of planets that can potentially support life per star that has planets.
Fl = the fraction of planets that could support life that actually develop life at some point.
Fi = the fraction of planets with life that go on to develop intelligent life (civilizations).
Fc = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space.
L = the length of time for which such civilizations release detectable signals into space.

We have a pretty good idea of what R * Fp * Ne is but the remaining factors are unknown.

An astronaut is standing on the surface of an alien planet. He is surrounded by giant mushrooms and in the sky, there is a large moon or a planet. — Exoplanet with life Stock Illustration ID: 1524001694 by Dotted Yeti

This is not really a super fact but more of a mystery. The goal of this blog is to create a list of what I call super facts. Important facts that we to be true, and yet they are disputed by many non-experts, or just highly surprising to the general public. However, I also post interesting facts and book reviews in this blog.

Is there Scientific Evidence for Alien Civilizations?

UFO sightings are not proof of alien spacecraft. The term “UFO” or “Unidentified Flying Object”, simply describes something in the sky that a person can’t recognize. Studies by NASA, Pentagon’s All-domain Anomaly Resolution Office show that the vast majority of these observations can be attributed to mundane phenomenon. Also, ask yourself, why would an alien civilization fly across interstellar space and only reveal themselves to random people with bad cameras and not to humanity as a whole. Why would they be flying around in little saucers? The typical flying saucer stories are not credible. Some UFO reports are also hoaxes or based on misidentified objects or misinterpretations of natural phenomena.

Grey alien with big black eyes showing peace sign, 3d render | Alien Civilizations and the Fermi Paradox — Alien showing peace sign. Shutter stock asset id: 2245224525 by adike

When I was in the Swedish army I was stationed near the Finnish Swedish border up north, which was close to Murmansk, a big Russian city which had the world’s largest navy base at the time. One night when I looked up in the sky I saw a shiny green elliptical shape in the night sky. It was quite big. I did not know what it was, but a lot of people called in to report it as a UFO. Were we being visited by space aliens as many believed. Some were even certain of it. No, it turned out to be Natrium cloud left behind by an intercontinental missile test launched from the Murmansk naval base.

A black hole with an orange accretion disk is approached by futuristic starship. — Was it a spaceship like this that we saw in the sky? No it was just a boring Natrium cloud left by a Russian missile. This spaceship approaching a black hole was generated by an Artificial Intelligence (AI) system. Stock AI-generated image ID: 2448481683 AI-generated image Contributor Shutterstock AI Generator.

Stories about past visitations are often guesses and conjecture mixed up with misrepresentation and fabrications. These stories are not taken seriously by scientists. SETI (Search for Extraterrestrial Intelligence) has not found any definitive evidence of alien life. SETI have not detected any signals that convincingly can be attributed to an alien intelligence. In summary, there is no scientific evidence for aliens in the declassified UFO videos, in purported alien bodies, mutilated cows or in anything else.

But why have we not found any traces of alien intelligence? Where is Everybody? That’s the Fermi Paradox.

Solutions to the Fermi Paradox

Interstellar travel and interstellar communication are incredibly difficult. Maybe we should take the fact that nothing can travel faster than the speed of light seriously. You can always speculate about warping space and wormholes but that does not mean such travel is at all physically possible. The distances in the universe are enormous and require thousands or millions of years of travel even at speeds close to the speed of light. Likewise, those distances make communication difficult. Perhaps interstellar travel and communication is too difficult to be worth it.

The so called “Great Filters” hypothesis suggests that advanced civilizations don’t last that long. Maybe they self-destruct in nuclear wars or germ warfare. Perhaps they burn fossil fuels causing severe global warming ending civilization. Maybe AI destroyed their civilization. There could also be a great filter before intelligent life occurs. What if life itself is extremely unlikely to happen.

The “Dark Forest” hypothesis suggests that advanced civilizations are hiding to avoid detection from hostile advanced civilizations. A related idea is that there is a very advanced civilization in our galaxy, which destroys all other civilizations when they become too advanced and a potential threat. If that is true, maybe we shouldn’t advertise our existence using projects like SETI.

Another suggestion is that advanced civilizations are extremely rare because they can only arise under extremely rare conditions. Not only does a planet need to be habitable, but plate tectonics, climate, the shape of continents and oceans all to be just right for intelligent life and advanced civilizations to evolve. Also, consider the fact that intelligent human life existed for hundreds of thousands of years before the rise of civilization. Perhaps we are the only civilization in our Galaxy. Perhaps we are the first civilization in our Galaxy.

Yet another suggestion is that beings that are part of advanced civilizations eventually will escape into a virtual reality world or escape into other alternative worlds.

Here is a video giving an overview of the Fermi Paradox

I would like to end with a famous quote by the famous science fiction writer Arthur C. Clark “There are two possibilities: either we are alone in the Universe, or we are not. Both are equally terrifying,”

So, what do you think? Where is Everybody?

To see the Super Facts click here

The Strange Worlds of Exoplanets

Superfact 13: The Strange Worlds of Exoplanets

Our sun is a star, and it has 8 planets Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune (as well as comets, asteroids, dwarf planets, etc.). The stars you see when you look up in the sky also have planets. We have identified 5,765 exoplanets (as of July 24^th, 2024) but there are billions more in our galaxy. Some exoplanets are similar to Earth, and some are very different from any of the planets in our solar system.

We know that exoplanets exist, we know some of them are in the so-called habitable zone and that some of them are very strange and interesting. This is certainly important knowledge for how we view our world and the Universe and yet many people who have not paid attention to astronomy news are very surprised to hear this information.

I’ve met many people who aren’t sure about the difference between a planet and a star, so being confronted with the news about exoplanets can be dizzying. That is why I am referring to the Strange Worlds of Exo Planets as a super-fact.

Star system model. Planets in orbit Straight front of sun. Solar system consisting of planets on a black background | The Strange Worlds of Exoplanets — Our solar system. From right to left, the Sun, Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. In the image the planets are lined up in a straight line and they are very close to each other. That is, of course, not realistic. Stock Photo ID: 2504532389 by ibnallahdin.

A bright star on the right and from right to left there are seven exoplanets | The Strange Worlds of Exoplanets — This is an imagined star/solar system. Notice that this solar system has seven planets, one less than our solar system. We would refer to these planets as exoplanets, if they were real. Stock Photo ID: 2466463165 by Nazarii_Neshcherenskyi

Most known exoplanets orbit stars roughly similar to the Sun but a lot of exoplanets have been seen orbiting red dwarf stars. It is estimated that there are 11 billion potentially habitable Earth-sized planets in the Milky Way. 40 billion if planets orbiting the numerous red dwarfs are included.

Habitable Zones

About 1 in 5 Sun-like stars have an “Earth-sized planet in the habitable zone. The definition of “habitable zone” is the distance from a star at which liquid water could exist on orbiting planets’ surfaces. Habitable zones<<Link-2>> are also known as Goldilocks’ zones, where conditions might be just right – neither too hot nor too cold – for life. The habitable zone for our solar system goes from the orbit of Venus to orbit of Mars with Earth in the middle.

It may seem strange that Venus is borderline in the habitable zone considering it’s hellish 870 degrees Fahrenheit. However, being in the habitable zone is no guarantee that the planet is habitable, and Venus got unlucky with its greenhouse gases (beginning about 2 billion years ago). Below you can watch a NASA video explaining about habitable zones.

Planets are extremely faint compared to their parent stars. For example, a Sun-like star is about billion times brighter than the reflected light from any exoplanet orbiting it. It is difficult to detect such a faint light source, and furthermore, the parent star causes a glare that tends to wash it out.

Just think about why you don’t see many stars during the day. They are still there and why you can’t see them is not because the sky is blue, but because the sun’s powerful light washes them out. Therefore, it is necessary to block the light from the parent star to reduce the glare while leaving the light from the planet detectable; doing so is a major technical challenge. All exoplanets that have been directly imaged are both large (more massive than Jupiter) and widely separated from their parent stars.

Size comparison between Earth, Jupiter, and Tres-4 | The Strange Worlds of Exoplanets — One of the largest known planets (by volume and mass) is TrES-4b Picture is from NASA.

The vast majority have been detected through indirect methods, such as the transit method. It should be noted that the official definition of the term planet used by the International Astronomical Union (IAU) (since they booted Pluto) only covers our Solar System and thus does not apply to exoplanets. My opinion : we may need another update on the definition of what a planet is as we continue making exoplanet discoveries.

Black dot on a bright star. — Exoplanet transiting in front of its star: Stock Photo ID: 2315686527 by muratart

Star surrounded by four specks that are slowly moving around the star as movie plays | The Strange Worlds of Exoplanets — One example of exoplanets that has been directly observed is the HR 8799 system. This system harbors four super-Jupiters orbiting with periods that range from decades to centuries. The footage below consists of 7 images of HR 8799 taken with the Keck Telescope over 7 years. The video was made by Jason Wang, data reduced by Christian Marois, and orbits were fit by Quinn Konopacky. Bruce Macintosh, Travis Barman, and Ben Zuckerman assisted in the observations.

Exoplanets Are Very Strange

Many of the exoplanets are very strange. Gliese 581 is about 20 light-years away from Earth and is very similar to earth, but it doesn’t rotate. The orbit of WASP-17b is the opposite of the rotation of its star (unlike our planets, and most exoplanets). Its radius is 1.9 times larger than Jupiter’s radius. In other words, its volume is 6.86 times larger than Jupiter’s and yet its mass is only half the mass of Jupiter making it a big light puff ball. Like giant cotton candy.

Gliese 436b, this planet has a core made up of ice (yes ice formed from water) that is as hot as fire. TrES-2b or Kepler-1b reflects less than 1% of the light it receives. It is darker than coal. 55 Cancri-e is believed to have an interior of diamond. In addition, the side facing its star/sun is extremely hot (1,700°C or 3,100°F).

A planet with an inside that is sparkling like a diamond. — A planet being cut in half, revealing a magnificent diamond inside. 55 Cancri e planet. The surreal world of cosmic gemstones. Stock Photo ID: 2381787311 by Dabarti CGI.

Then we also have J1407b, an exoplanet six times as massive as Jupiter and 20 times as massive as Saturn but with a ring system that outshines that of Saturn by far. J1407b is often referred to as Super Saturn.

A planet surrounded by rings that are hundreds of times wider than the planet. — The rings of Super Saturn. J1407b is an exoplanet 20 times more massive than Saturn. Stock Illustration ID: 2329821675 by Love Employee.

Determining what materials exoplanets consist of is very difficult but NASA believe they’ve found water planets. Check out this video from NASA and the illustration below.

A comparison between Earth (left) and Kepler-138 d (right). The planets are cut like apples so we can see the inside cores. Kepler-138 d has a very deep ocean. — This is an artist’s illustration showing a cross-section of the Earth (left) and the exoplanet Kepler-138 d (right). Like the Earth, this exoplanet has an interior composed of metals and rocks (brown portion), but Kepler-138 d also has a thick layer of high-pressure water in various forms: supercritical and potentially liquid water deep inside the planet and an extended water vapor envelope (shades of blue) above it. These water layers make up more than 50% of its volume, or a depth of about 1,243 miles (2,000 kilometers). The Earth, in comparison, has a negligible fraction of liquid water with an average ocean depth of less than 2.5 miles (4 kilometers).

NASA also believe they have found water vapor in a small exoplanet’s atmosphere, GJ 9827d. Check out the video below.

Below is an imagined exoplanet with mushroom like life

So, it is estimated that there are 11 billion potentially habitable Earth-sized planets orbiting stars roughly the same size as the sun in the Milky Way. It is estimated that there are an additional 40 billion potentially habitable Earth-sized planets orbiting red dwarf stars in the Milky Way.

The NEID Spectrometer

As you can see in the comment section below, a fellow blogger and on-line friend David Lee Summers mentioned that looking at exoplanets is his “day” job! He spent the last three nights helping to take spectra of exoplanet systems with the WIYN telescope at Kitt Peak. They work with the NASA-funded NEID spectrometer.

A spectrometer is a scientific instrument that measures the distribution of light wavelengths, or the spectral components of a physical phenomenon It is amazing what you can find out from star light, the weight of exoplanets, the size of stars, the elements and substances in stars and planets. Below is the extreme-precision radial-velocity spectrograph mounted on the WIYN 3.5-meter Telescope at Kitt Peak National Observatory. That is the instrument David works with.

David wrote a blog post about his work which I will re-blog in the near future.

The blue NEID port adapter used for measuring the weight of exoplanets and more. — Image of the NEID fiber feed (Port Adaptor) mounted on the WIYN telescope obtained during commissioning of the instrument. The Port Adaptor feeds light from the telescope to the NEID instrument, which is located on another floor of the building, below the telescope. The WIYN 3.5-meter Telescope at Kitt Peak National Observatory is located near Tucson, Arizona. Click on the image to visit the NOIR lab and read about the NEID spectrograph.

Thank you so much David.

Do you believe there’s intelligent life on any of them? If you do, why haven’t we heard from them?

Tag: Exoplanets