Did you know that the Moon and space itself have a smell? Space has a lot of surprises. Here are the 10 lesser-known space facts.

1. You could fit all the planets in the solar system between the Earth and the Moon

All the planets of the Solar System could fit in the distance between the Earth and the Moon, which is around 384,400 km (238,855 miles).

2. The Moon and space have a smell

The Moon smells of burnt gunpowder, space smells like hot metal and seared steak.

Moondust. “I wish I could send you some,” says Apollo 17 astronaut Gene Cernan. Just a thimbleful scooped fresh off the lunar surface. “It’s amazing stuff.”

Feel it-it’s soft like snow, yet strangely abrasive.

Taste it-“not half bad,” according to Apollo 16 astronaut John Young.

Sniff it-“it smells like spent gunpowder,” says Cernan.

Source: NASA

Astronauts that have spent time in space have reported that space smells like a variety of things. So, what exactly does space smell like?

3. The Sun is the most difficult place to get in the solar system

It sounds counter-intuitive, but despite it contains 99.8 percent of the mass in our solar system, the Sun is the most difficult place to get in the solar system.

Why is it so difficult? The answer lies in the same fact that keeps Earth from plunging into the Sun: Our planet is traveling very fast – about 67,000 miles per hour (108,000 km/h) – almost entirely sideways relative to the Sun. The only way to get to the Sun is to cancel that sideways motion.

In more technical terms, the Δv to enter Hohmann orbit
from Earth’s orbit is 29.8.

In astrodynamics and aerospace, a delta-v budget is an estimate of the total change in velocity (delta-v) required for a space mission.

Compare that number (29.8) the Δv to go to Saturn (10.3), to Pluto (11.6), or to infinity (12.3).

For example, the New Horizons space probe to Pluto achieved a near-Earth speed of over 16 km/s which was enough to escape from the sun. It also got a boost from a fly-by of Jupiter.

The Sun contains 99.8 of the mass in our solar system. Its gravitational pull is what keeps everything here, from tiny Mercury to the gas giants to the Oort Cloud, 186 billion miles (300 billion km) away. But even though the Sun has such a powerful pull, it’s surprisingly hard to actually go to the Sun: It takes 55 times more energy to go to the Sun than it does to go to Mars.
Why is it so difficult? The answer lies in the same fact that keeps Earth from plunging into the Sun: Our planet is traveling very fast – about 67,000 miles per hour (108,000 km/h) – almost entirely sideways relative to the Sun. The only way to get to the Sun is to cancel that sideways motion.
Since Parker Solar Probe will skim through the Sun’s atmosphere, it only needs to drop 53,000 miles per hour (85,000 km/h) of sideways motion to reach its destination, but that’s no easy feat. In addition to using a powerful rocket, the Delta IV Heavy, Parker Solar Probe will perform seven Venus gravity assists over its seven-year mission to shed sideways speed into Venus’ well of orbital energy. These gravity assists will draw Parker Solar Probe’s orbit closer to the Sun for a record approach of just 3.83 million miles (6.16 million km) from the Sun’s visible surface on the final orbits.
Though it’s shedding sideways speed to get closer to the Sun, Parker Solar Probe will pick up overall speed, bolstered by Sun’s extreme gravity – so it will also break the record for the fastest-ever human-made objects, clocking in at 430,000 miles per hour (612,000 km/h) on its final orbits.

4. Jupiter’s satellite Ganymede is the only moon in the solar system known to have its own magnetic field

Jupiter’s moon Ganymede has a diameter of 5,268 km (3,273 mi) and is 8% larger than the planet Mercury, although only 45% as massive.

It is s the largest and most massive moon in our solar system.

But, it has many more amazing features other than being the largest moon – for example, it is the only moon known to have a magnetic field, which is probably created by convection within its liquid iron core.

Lesser-known space facts: Earth-Ganymede-Moon size comparison
Size comparison of Earth, the Moon, and Ganymede. The radius of Earth at the equator is 6,378 kilometers (3,963 miles). Ganymede has a mean radius of 2634.1±0.3 km (about 1636 miles, 0.413 Earths). Moon’s radius is 1,737.1 km (1079 mi).

5. There is water ice on Mercury

The smallest and innermost planet in the solar system, Mercury has an average surface temperature of 332 °F (167 °C).

But, it displays the most extreme range of surface temperatures of any celestial body in the Solar System. Regions that receive direct sunlight at the equator reach maximum temperatures of 700 K (800° F), whereas regions in permanent shadow in high-latitude craters can drop below 50 K (-370° F).

At these very low temperatures, water ice is thermally stable over billion-year timescales, according to NASA.

Observations from the Messenger probe that orbited the planet Mercury between 2011 and 2015 (“MErcury Surface, Space ENvironment, GEochemistry, and Ranging” – MESSENGER) showed that the permanently-dark (hence very cold) areas on Mercury definitely have water ice. That water ice is partially covered by dark organic deposits.

6. Nothing can move through space faster than the speed of light, but space itself can expand faster than light

Meaning in the distant (very distant!) future we won’t be able to see galaxies outside our own.

About 1034 years in the future, as the expansion of the Universe accelerating, it will begin to spread matter apart faster than the speed of light. By this point, even the light can’t travel between the stray matter – the secrets of the cosmos will be locked away forever.

7. Saturn is not the only ringed planetary body in the Solar System

The other three giant planets (Jupiter, Uranus, and Neptune) also have ring systems. But, the most prominent and most famous planetary rings in the Solar System are those around Saturn, as everybody knows.

But, the gas giants aren’t the only celestial bodies that have rings: in 2014, for example, astronomers discovered rings were discovered around the asteroid (a centaur -a small Solar System body with either a perihelion or a semi-major axis between those of the outer planets) named 10199 Chariklo.

So far, six ring systems discovered in the solar system: around (in order of discovery) Saturn, Uranus, Jupiter, Neptune, 10199 Chariklo, and Haumea, a dwarf planet in the Kuiper Belt.

2060 Chiron, another centaur, is also suspected to have a pair of rings.

Saturn by Gordan Ugarkovic
This view of Saturn was created made by the amateur image processor and Cassini fan Gordan Ugarkovic from images obtained on October 10, 2013. It was chosen as NASA’s image of the day for October 17, 2013. You can see the full-resolution image on NASA’s web site.

8. The Sun’s upper atmosphere is 300 times hotter than its surface

The sun’s surface is blisteringly hot at 10,340 degrees Fahrenheit (5,730 degrees Celcius), but its atmosphere is another 300 times hotter. And nobody knows why, for now. But there are some theories.

9. There’s a special type of a neutron star called “magnetar”, and if you get too close one of them, your molecular structure would be disintegrated

Magnetars have the strongest magnetic fields known.

They are so strong that if you get within a thousand kilometers of a magnetar the magnetic field kills you by stripping the electrons from the atoms in your body. That is strong!

The most powerful magnet on Earth right now is about 410,000 Gauss.

A magnetic field of a magnetar can be as strong as one quadrillion gauss. That’s a one with 15 zeros behind it.

What If a Magnetar Entered Our Solar System? A Magnetar is the most powerful object in the Universe. The biggest spinning magnet to ever exist. It would just turn all your atoms to dust.

10. Galaxies can have satellite galaxies – our Milky Way has too

Galaxies can have satellite galaxies – galactic moons if you will.

In other words, just like the Moon orbits the Earth, and the Earth orbits the sun, galaxies orbit each other.

More than 50 discovered satellite galaxies orbit our own galaxy, the Milky Way.

What’s more, according to a new study, quite a few of them were stolen from other galaxies.

Sources

“The Mysterious Smell of Moondust” on the NASA website
“Water Ice on Mercury: How It Stays Frozen” on Space.com
“25 weirdest facts about the Solar System” on Space.com
“It’s Surprisingly Hard to Go to the Sun” on the NASA website
Delta-v budget on Wikipedia
Ganymede on Wikipedia
Ring system on Wikipedia

M. Özgür Nevres

I am a software developer, a former road racing cyclist, and a science enthusiast. Also an animal lover! I write about the planet Earth and science on this website, ourplnt.com. You can check out my social media profiles by clicking on their icons.

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