Which planet in our solar system would be the most difficult for humans to land on safely?

 To find the hardest planetary landing in our solar system, you have to choose between a world with no surface at all, or one where the air is hot enough to melt lead.

Attempting to land on a gas giant like Jupiter is a paradox because the planet lacks a solid surface.

Jupiter, as seen by the Cassini spacecraft in 2000. It lacks a solid surface, making a traditional landing impossible.

Jupiter is composed almost entirely of hydrogen and helium. A crewed spacecraft entering its atmosphere would experience a descent with no end. After passing through turbulent, ammonia-rich clouds and lethal radiation belts, the ship would face exponentially increasing pressures and temperatures. Eventually, the pressure becomes so immense that hydrogen gas compresses into a bizarre state called liquid metallic hydrogen. Any vessel would be crushed, melted, and assimilated into the planet's interior long before reaching the core. Because there is no rocky crust to park a vehicle on, a safe landing is physically impossible.

For a true planetary landing on a solid surface, Venus provides the most hostile environment for human survival.

An illustration of a heavily armored spacecraft descending through the thick, hostile sulfuric acid clouds of Venus.

From orbit, Venus looks like a serene, bright marble, but its atmosphere is a nightmare for aerospace engineering. The atmosphere is composed primarily of carbon dioxide, with thick clouds of sulfuric acid. The atmospheric pressure at the surface is roughly 90 times greater than that of Earth. Standing on the surface of Venus would feel akin to being submerged 900 meters (about 3,000 feet) underwater. Any unreinforced habitat or spacesuit would instantly implode from the weight of the air alone.

In addition to the crushing pressure, Venus experiences a runaway greenhouse effect. The surface temperature averages around 475 degrees Celsius (887 degrees Fahrenheit). This is hot enough to melt lead, zinc, and tin. The extreme heat would instantly cook conventional life-support systems, melt electronics, and rapidly degrade spacecraft seals.

A panoramic view of the surface of Venus captured by the Soviet Venera 13 lander in 1982.

Despite these apocalyptic conditions, Soviet engineers managed to land robotic probes on Venus during the Cold War. Because the atmosphere is so incredibly dense, the later Venera landers did not even need parachutes for the final stages of their descent; they used aerodynamic braking discs to drift down through the thick, fluid-like air.

Once on the ground, the engineering challenge shifted entirely to survival. The Venera 13 robotic lander, which touched down in 1982, holds the record for the longest survival time on the Venusian surface. It lasted for just 127 minutes before the immense heat and pressure breached its protective titanium hull and destroyed its instruments. Designing a crewed lander to keep humans alive long-term on Venus would require specialized high-temperature refrigeration, massive titanium pressure hulls, and materials that push the boundaries of materials science.

While Mars presents difficulties with its thin atmosphere and dust storms, aerospace engineers plan to eventually send humans to visit and inhabit it. On Venus, achieving even a few hours of robotic surface time represents an engineering marvel, making it the single hardest planetary surface in the solar system for humans to reach and survive on.

What is the biggest solar system in our galaxy?

 We know definitively what the biggest solar system in our galaxy is. It’s ours! Our sun and planets.

Because it is the only one called the “solar system”, since “solar” comes from the word “sol” or “sun”. So it’s literally the system of bodies around the sun.

But when we correct that to “star system”, we really have no idea what the largest one is. As strange as it sounds, we know orders of magnitude more galaxies than star systems. So the odds are overwhelming we have not found the largest star system in the galaxy.

However, all jokes aside, it is possible that our own solar system may be up there. The largest star system we have found to date is Kepler-90, with 8 known planets. That happens to be the same number of planets in our solar system. However, smaller planets are difficult to find in other star systems so Kepler-90 very well could have more hiding in there.

Will we ever leave our solar system? By what means might we do that?

 The biggest challenges are Time and Energy ! It will take a lot of onboard energy that has to run for centuries !

Total non returnable trip time to nearest solar system (4 light years ) in proposed ship at max speed 4% speed of light , 12,000 km/per/sec. 300 years.

If we built a sufficiently large space ship in earth orbit maybe with internal volume of at least 10,000,000 cubic meters (approx 3 times the size of NASA Vehicle Assembly Building ) and would be constructed of very light composites and super alloys to keep weight down . It will also be fitted with 5 nuclear power stations that can run for 50 years without refuelling (fast breeder reactor type) and 350 years worth of fuel and spare parts totaling 30,000 tons . It will also have a 3D printing workshop where anything can be duplicated including high strength metal components.

Accommodation for 2000 crew and families , plus food for 10 years and a highly efficient recycling system and very large hydroponic growing system . Plus 100,000 tons of water . There would be no shortage of heat as the power plants will put out prodigous quantities of waste heat that will be utilized throughout the ship which will be transported by water .

Everybody on board would work and families would be expected to start having children in a designated time period to replace people that had passed on , pop. limit 2500–3000 people . The ship will have a very large diameter and will spin at approx 1.2 rpm producing normal gravity in the Toroid (main living) and various other gravity gradients through out the rest of the ship . Large area on center line of ship reserved for very low gravity sports .

Nothing could be discarded from the ship in interstellar space , everything will have to be recycled including people that pass on, there will be no such thing as garbage ! Schools/ Universities on board plus a plethora of entertainment possibilities for everyone . Everything that is required to keep people sane for centuries.

Propulsion ? With a large amount of electricity available (40,000 megawatts ) a large number of NASA Evolutionary Xenon Thrusters (NEXT) would be the most viable propulsion engines today using xenon gas as fuel . The ship would need 300,000 tons of Xenon Liquid (102,000 Cubic Meters ) and a total ship weight of 600,000 tons.

Say 35,000 megawatts available to engines would deliver 121,730 kilograms of thrust from the Xenon fueled engines .

It would take 100 years of acceleration to achieve 4% of c and travel just over 1 light year then cruise for 50 years to traverse 2 light years then 100 years of de-acceleration as it approached new star system . Total trip time 300 years , total distance traveled 4 light years to Alpha Centauri Star system .

At this velocity relativistic effects are rather minor. Ship time will be dilated down to 3.9967987189749747 years instead of 4. So the occupants of the ship will be approx 4 minutes younger than those left on earth !

What is the largest thing in the solar system?

 

It's not Sun.

It's the magnetic field of Jupiter.

See, jupiter is a big planet, but looks puny against its magnetic field.

Charged particles in the solar winds stretch the field away from Sun, like a comet's tail.

It stretches 7 million km towards the Sun, and over a billion km in the opposite direction— Saturn orbits inside it sometimes.

If you could see the field from Earth, it would appear 5 times larger than a full moon.

Jupiter's magnetic field is roughly 20,000 times stronger than Earth's. What generates it?

Deep beneath the clouds, the pressure is so high that hydrogen is crushed to a metallic liquid, and conducts electricity.

This conductive ocean rotates around the core at high speeds. It generates electricity like a dynamo.

Jupiter's magnetosphere also creates stunning auroras. They're not larger than earth’s auroras, but larger than Earth.

What’s the coldest thing in the solar system?

 

Neptune’s moon Triton.

It gets as cold as -235°C. But that isn't what makes it so weird.

Neptune has 14 moons. With the exception of Titan, all the moons are very small, and come in two varieties— regular and irregular.

The regular ones orbit close to the planet, and irregular ones are generally farther from Neptune, with all sorts of crazy orbits..

And then there's Triton. It was discovered by amateur astronomer William Lassell, who, in 1846, spotted the moon a mere 17 days after the discovery of Neptune itself.

There are many reasons that make it strange.

For one, Triton is big. The 7th largest moon of Solar System. It’s over 200 times bigger than all the other moons of Neptune combined.

Second, it's one of the irregular moons, for it orbits the wrong way. It orbits backwards relative to Neptune’s spin, and orbit is almost perpendicular to its parent planet.

Third, it looks like a cantaloupe.Covered in bumpy, wrinkly features nicknamed cantaloupe terrain.

Fourth, it's actually no mere moon, but instead a victim of an interplanetary kidnapping.

Triton is likely a Kuiper belt object, like Pluto and Eris. Long ago, it fell into the vicinity of Neptune and got captured by the planet’s gravity.

Either Triton just got unlucky and had the exact wrong orbit to land itself near Neptune, or it suffered some collision with one of Neptune's own moons and losed enough energy to remain in orbit.

Sadly, it's future isn’t bright either. Due to tidal forces Triton’s orbit is decaying, and it's slowly spiralling into its doom. It’ll either crash into Neptune or will be ripped apart into a spectacular ring system— more dazzling than Saturn's..

Which is the biggest planet and smallest planet of our solar system?

 The largest planet in the solar system is Jupiter, and the smallest is Mercury.

…

Hah, you think I am just going to write some super short answer? Please, that’s just is not my style.

So, let’s start off with the smallest, and one of the coolest planets in my opinion:

Mercury!

Ahh, good ol’ Mercury.

Mercury is the smallest, and innermost planet of our solar system. It is quite similar to our very own Moon, both in looks and surface features. In fact, I like to look at Mercury as the inverted color version of the Moon, because the higher areas of Mercury are darker, and the deep craters are brighter (opposite of our Moon.) Some of these craters, in fact, are so deep, sunlight never reaches parts of those craters. And, in some of those craters, there is actually water ice, just hanging out. This is quite amazing, since the day time temperature on Mercury can reach several hundred degrees Fahrenheit.

Another really cool thing about Mercury is that it has an unusually large iron and nickel core for its size. Scientists think that the core makes up 85% of the planets entire radius. This also makes it the second densest planet, only behind the Earth. Scientists have two different theories as to why the core of Mercury is very large.

The first, and older theory is that Mercury had a collision with another planet when it was first forming, and this blew off most of the silicates and lighter stuff off of baby Mercury and the other planetoid, while also merging the two cores of the planets, making one smaller planet, but with a huge core.

The second, and more exciting theory is that Mercury, a long time ago, used to be a gas giant. But, as it got closer and closer to the sun, more and more of the gas was stripped away from the intense solar winds, until all that was left was a small, metallic core that most gas Giants have. This theory is really cool because it would make our solar system seem a bit more normal, since many other stars have gas giants that orbit really close in to its parent star, but ours does not. It is also a nice feeling to think Mercury used to be a giant once upon a time.

Now, for the largest planet in the Solar System:

Jupiter!

Jupiter is a lot different from Mercury, in almost every way imaginable. First of all, Jupiter is HUGE. Jupiter has a radius of 43,441 miles, compared to tiny Mercury, which only has a radius of 1,516 miles. This means that you could place 28 Mercury-sized planets next to each other, stretch them in a straight line above Jupiter, and Jupiter would still have a larger diameter. Jupiter also has a very thick hydrogen atmosphere, with a cloud layer 30 miles thick, before you reach a point inside Jupiter that is very bizarre.

Once you get past that cloud layer, the hydrogen is so dense now that it takes on a liquid form. But, this isn’t a cold liquid, but is extremely hot, like the molten parts of our planet, only made of hydrogen gas. Past this layer, the hydrogen continues to become more dense to the point it acts like a superheated metal. At this point, anything inside would be burnt beyond recovery, but if you were to send something down there, this is as far as you could get. Below the metallic layer of hydrogen, you have a small rock and ice core (similar to Mercury, actually).

Jupiter has the most moons in the solar system as well, counting 67 so far. Most of these moons are small asteroids that were caught by Jupiter’s immense gravity, but 4 of them, the Galilean moons, are quite unique. The closest one in is Io, which is one of the most volcanically active objects in our solar system, and its surface has a weird mix of colors. Europa has a huge water ocean underneath its thick icy crust, and it is a possible contender to support life because of that. Callisto has one of the oldest surfaces in the solar system, and Ganymede is the largest moon in the solar system, and is bigger than Mercury.

So, there you have it, the largest planet in our solar system, and the smallest, along with some cool details and theories about them. And no, Pluto doesn’t count, it’s classified as a dwarf planet, so leave it at that.

Is it safe to drink water during a solar or lunar eclipse?

 Scientifically, it is perfectly safe to drink water during a solar or lunar eclipse. The celestial events have no effect on the chemical or physical properties of water, and there's no scientific evidence to support the idea that water or food becomes "contaminated" or unsafe during an eclipse.

​Understanding the Science Behind Eclipses 🌑

​A solar eclipse occurs when the Moon passes between the Earth and the Sun, casting a shadow on Earth. A lunar eclipse happens when the Earth passes between the Sun and the Moon, and the Earth's shadow falls on the Moon. These are purely astronomical events. The light and radiation from the sun are not different during an eclipse; the only change is the amount of sunlight that reaches us, which is blocked by the moon's shadow. The sun still emits the same electromagnetic radiation, which doesn't affect food or water on Earth.

Cultural Beliefs and Myths 📜

​The belief that it is unsafe to eat or drink during an eclipse is a cultural and traditional one, not a scientific one. In some cultures, particularly in parts of India, it is believed that the period of an eclipse, known as "Sutak," is inauspicious. During this time, people are advised to fast, avoid cooking, and not consume food or water. These beliefs are often rooted in ancient mythologies that describe eclipses as a time when negative cosmic energies are high, which could contaminate food and affect a person's health.

​The practice of placing tulsi (basil) leaves in food and water during an eclipse is also linked to these beliefs. While it is believed to have a symbolic purpose of purification and protection from negative energies, basil leaves are also known to have natural antibacterial properties, which may have served as a practical way to prevent bacterial growth in a time when refrigeration was not available.

​Ultimately, from a scientific standpoint, there is no harm in drinking water or consuming food during a solar or lunar eclipse. The decision to abstain is a matter of personal or cultural belief.

Mercury is the innermost planet of the Solar System.

 In particular, it is located 58 million km from our star, just over a third of the distance that separates the Earth from the Sun. At this distance corresponds a revolution period, the Mercurian year, of 88 days.

Like all other celestial objects, Mercury also rotates on its axis. Unlike other planets like Earth or Mars, Mercury rotates on itself very slowly, completing a full rotation every 59 days.

In the title of this post, I wrote that a day on Mercury lasts more than a year, but if math is objective, 59 is smaller than 88, so in theory, the year is the longer period of time between the two.

However, this depends on the definition we want to give to the word "day". If by day we mean the period it takes for a planet to complete one rotation on its axis, then a year on Mercury lasts more than a day. This definition is known as a sidereal day.

However, we could consider the day to be the time that elapses between two consecutive culminations of the Sun (that is, when the Sun passes the meridian and reaches its maximum height in the sky). This day is known as the solar day.

The solar day is longer than the sidereal day, since due to the revolution around the Sun the planet must rotate a little more to bring the Sun back to culmination compared to the previous day.

The difference between the two days on Earth is minimal, only 4 minutes. However, on Mercury, while the sidereal day lasts 59 Earth days, the solar day lasts a whopping 176 Earth days! This means that between two consecutive passages of the Sun in the same position in the Mercurian sky, a full 176 days pass!

Depending on the definition of day we choose, here is how on Mercury a day can last longer than a year.

Credit: NASA.

What is the weirdest moon in the solar system?

 I’m gonna go with Saturn's moon Iapetus.

(In Greek mythology, Iapetus is a Titan, a son of Uranus and Gaia, and the father of several well-known figures, including Atlas and Prometheus)

Take a look first

You're seeing this, right? That weird ring of mountain range around the Moon?

So here's what we know about this peculiar ring:

Its average height is 20 KM (about 12 miles), making it the third tallest mountain range in our solar system.

It circles the entirety of the Moon.

And it does so exactly around its equator.

And we haven't the faintest clue as to why.

There are hypotheses: Maybe Iapetus, just like Saturn, the planet it is orbiting, had rings. These rings may have gradually been grown to the moon and eventually crashed, forming the range.

Another suggests that iapetus turned around its axis in extremely high speeds, causing it to warm up and then for some reason slowed down, perhaps abruptly and as it was cooling off it's two halves sort of melted into each other creating this bulge.

Volcanic activity is probably not the answer because Iapetus has a very low density, only slightly greater than that of water ice. This indicates that it's composed predominantly of water ice with only a small fraction of rocky material (around 20%), so this pretty much takes volcanic activity off the list.

So what we can say with certainty is that we haven't got a clue.

But it's a heck of a question.

These photos by the way were taken in 2007 by the cassini probe.

Weird enough, right?

Wrong. It gets weirder. Let's zoom out.

This isn't shade or an area not facing the sun while the photo was taken - Iapetus is spllit into two drastically different hemispheres.

One hemisphere of Iapetus is extremely dark, almost as dark as coal, with a reddish-brown tint. The other hemisphere is remarkably bright, covered in ice, almost as reflective as Europa (one of Jupiter's moons).

The transition between these two very different terrains is quite sharp and distinct, resembling a "yin-yang" or the stitching on a baseball.

Scientists believe the dark material is accumulated dust and debris, primarily from another distant Saturnian moon, Phoebe. Iapetus is tidally locked to Saturn, meaning one side always leads in its orbit, effectively "sweeping up" this dark material like bugs on a car's windshield.

Why? Is that dust the explanation? 🤷 Don’t know.

What we do know is that the dark material absorbs more sunlight and heats up. This causes any ice in the dark regions to vaporize away, leaving behind even darker, carbon-rich residues. The vaporized ice then re-deposits in colder, brighter regions (like the poles or the trailing hemisphere), making those areas even brighter. This process, called thermal segregation, intensifies the already existing color contrast.

Well, a mountain range on the equator and two tones. strange enough!

Nope.

It keeps getting stranger.

Look again:

Iapetus has a weird shape.

It’s oblate Spheroid, but… it's not supposed to be.

Iapetus is oblate spheroid, meaning it's flattened at the poles and bulges at the equator, which is common for rotating bodies (like Earth, which bulges slightly at its equator due to its spin).

So that would work with a moon that would have been spinning much faster in its early history, with a rotation period of only about 16 hours.

But Iapetus is currently tidally locked with Saturn, rotating once every 79 Earth days…

This means Iapetus somehow froze its shape when it was spinning rapidly and then later slowed down its rotation drastically, but its rigid crust retained its original, faster-spinning form. How it slowed down so quickly, given its distance from Saturn, is a subject of debate.

To explain, Iapetus orbits much farther from Saturn than the other major inner moons (like Titan, Rhea, Dione, Tethys, Enceladus, Mimas) and this didn't happen to them.

Well, at least the Orbit is not weird! …is it?

Of course it is.

Most of Saturn's moons orbit pretty much around its equator.

But not Iapetus (of course). Iapetus has a 15 degree inclination, that means sometimes it’e moving up above the equatoral orbit, and sometimes down below it.

Because why not?

The combination of its two-tone surface, the inexplicable equatorial ridge, its "fossil" shape indicating a past rapid spin, and its unusual orbit truly makes Iapetus one of the most mysterious and captivating objects in the solar system. Scientists are still actively researching and debating the origins of these bizarre features.

Iapetus isn't just the weirdest moons in our solar system, in my humble opinion. It's probably one of the weirdest places in our solar system, period.

I think it's awesome.