At best we can speculate about GJ 357d. The case of GJ 357d we have a scientific paper which is about a planet that is in the habitable zone of its star, is at least six point one times the mass of the Earth, based on what we see, and we do not even know its radius (Luque, et al. 2019). Yet the news media writes and reports on it as if we knew for certain it is Earth like. (A brief word on Jessica Yaniv follows.)
Without knowing the radius of the planet, we cannot know its density. Without knowing its density, we cannot know if it is a small gas giant or a large terrestrial planet. Therefore, any reporting that this is an “Earth like” planet is speculation at best.
The probability that this planet is a small Neptune or Uranus type planet is AT LEAST as likely or even more likely. Just look at our own solar system. We have as many gas planets as terrestrial ones. Until we know more and based on what we know about the star system we know best, the simple truth is WE DON’T KNOW about GJ 357d. We have, AT BEST, a 50/50 chance of it even being Earthlike. Which is the state of maximum ignorance on a subject …not a good chance.
Once we have an Earth mass, earth size (and therefore rocky), planet in the habitable zone we will have one leg of the three-legged stool of information, upon which speculation or hypotheses about life can rest, and be reasonable. For now, all we can do is speculate.
What would life be like on GJ357d.
After saying all the, above I will speculate like a scientist. Grant the two following suppositions. GJ357d is a rocky, and habitable, planet about 1.5 times the radius of the Earth.
If so, we can figure out how strong gravity would be on the surface of this planet. It is an equation derived from combining Newtons second law with Newton’s universal law of gravitation. Then plugging in the relevant numbers. The acceleration due to gravity on this planet would be 27 m/s^2. Gravity would be almost three times as strong (2.7 times, to be precise). So, a 150 lb person would weigh 450 lbs. If we landed there the gravity would crush us flat. Best case scenario the experience would be like the following video.
Worst case, and most likely case… internal organs would be squished to such an extent they could not function. The heart could not fight the gravity. The contents of the digestive tract would rip out and into the body. The connective tissues connecting muscles to bones would tear. Finally, death… just as if 300 lbs of steel fell on top of the body.
I am not a physiologist though so maybe that wouldn’t happen. Maybe if you survived, somehow, it would be like you were lifting hundreds of pounds every moment of every day even as you slept? Not very likely.
Realistically, life native to such a planet would evolve in a completely different way to life on Earth. It may evolve to be flat, with no brittle bones. It may evolve to use some other mineral, say iron, in its bones. It may do anything that is physically and chemically possible to fight gravity there. Thus, making it, in one respect, stronger than we could ever be. Intelligence, can exist where there is life but it is hardly required.
In conclusion it is unlikely that there is life there. We really have no idea if this planet is a super Earth or a mini Neptune. It is unlikely that this planet would be a place we’d want to visit if it is habitable. Aliens, intelligent or not, from such a planet would be far stronger than us. It’s probably best we give them a wide birth…if they exist.
Before I forget, mainstream media, PLEASE stop hyping every paper like this. Scientific publications are almost always very careful statements about the probabilities that X or Y will be the case. Its s great that you are interested. Either write your reports such that these probabilities are stated up front, in the first few lines OR don’t write them at all.
IF it turns out to be habitable, I propose we name it Planet Vegeta. In honor of the fictional home of the Saiyajin from Dragon Ball which was an Earth like planet with 10x the surface gravity of Earth. Which is no sillier than a name from Greek myths, and which fits it physically
Luque, R, E Palle, D Kossakowski, S Dreizler, J Kemmer, N Espinoza, and et. al. 2019. "Planetary system around the nearby M dwarf GJ 357 including a." Astronomy and Astrophysics. doi:10.1051/0004-6361/201935801.
Toriyama, Akira. 1990. "DragonBall Z." Shonen Jum and Toei Animation. Shonen Jum and Toei Animation. Tokyo. https://www.youtube.com/watch?v=vTyUe1js-aw.
PS On Jessica Yaniv
As a brief postscript I comment here on the curious case of Jessica Yaniv. They are known around the net as a transgender woman from Canada who want to force service providers to wax them. They want to organize a pool party with people age 12 and up no parents around. Most post op transwomen in Canada will have had genital electrolysis, so I am suspect that they couldn’t find anyone at all to help with waxing. Most transgender youths are highly self-conscious of their bodies at that age. So, who is this really for?
Unlike the properties of GJ 357 d I can answer this one. Like any group of people, some transgender people are attention seeking narcissists. It’s all for and about them. Please do not make the mistake of using what one fool does to disparage a whole group. Plus, in this interview she says some nasty things about Sikhs.