My Science School

The largest planet in the solar system, the gas giant Jupiter is approximately 318 times as massive as Earth. If the mass of all of the other planets in the solar system were combined into one "super planet," Jupiter would still be two and a half times as large.

Jupiter has a mean radius of 43,440.7 miles (69,911 kilometers), about a tenth that of the sun. However, its rapid rotation — it spins once every 9.8 hours — causes it to bulge at the equator, where the diameter is 88,846 miles (142,984 km). In contrast, the diameter at the poles is only 83,082 miles (133,708 km). This stretched shape is known as an oblate spheroid.

If you were to walk around the equator of Jupiter, you would travel 272,946 miles (439,264 km), over 10 times the distance around Earth's center line.

Because Jupiter is made of gas, mostly, its surface is considered uniform. As such, it lacks high and low points — mountains and valleys — such as those found on rocky terrestrial planets.

Credit : Space.com

Picture Credit : Google

What’s the closest planet to our own? Common sense would say the answer is either Mars or Venus, our next door neighbors. Of the two, Venus comes closer to the Earth than any other planet and its orbit is closest to ours. But as an article in Physics Today points out, over half the time Venus is not the nearest planet; Mercury is. In fact, the scientists behind the article crunched the numbers and found that on average, Mercury is the closest planet not only to Earth but to every other planet in the solar system as well.

The scientists developed a simulation of our solar system featuring all of the planets moving in their orbits. They let the planets orbit for thousands of simulated years, all the while calculating the distance between any two of them. The scientists then averaged those values together to find which planets are the closest to each other over time.

Surprisingly, they found that Mercury was the closest planet to all seven other planets. This might seem impossible, but it makes sense if you realize that every planet spends about half its time on the opposite side of the Sun. In Earth’s case, while Venus does get very close to Earth it also spends plenty of time very, very far away.

This is a very different way to calculate the ‘closest planet’ than most people use; typically, the distance from one planet to another is taken to mean the distance between the two planets’ orbits. But this result shows there’s more than one way to define our closest neighbor.

Credit : Physics Today 

Picture Credit : Google

The heaviest artificial objects to reach space include space stations, various upper stages, and discarded Space Shuttle external tanks. Spacecraft may change mass over time such as by use of propellant.

Currently the heaviest spacecraft is the International Space Station, nearly double Shuttle-Mir's mass in orbit. It began assembly with a first launch in 1998, however it only attained its full weight in the 2020s, due to its modular nature and gradual additions. Its mass can change significantly depending on what modules are added or removed.

The ISS was originally intended to be a laboratory, observatory, and factory while providing transportation, maintenance, and a low Earth orbit staging base for possible future missions to the Moon, Mars, and asteroids. However, not all of the uses envisioned in the initial memorandum of understanding between NASA and Roscosmos have been realised. In the 2010 United States National Space Policy, the ISS was given additional roles of serving commercial, diplomatic, and educational purposes.

The ISS provides a platform to conduct scientific research, with power, data, cooling, and crew available to support experiments. Small uncrewed spacecraft can also provide platforms for experiments, especially those involving zero gravity and exposure to space, but space stations offer a long-term environment where studies can be performed potentially for decades, combined with ready access by human researchers.

The ISS simplifies individual experiments by allowing groups of experiments to share the same launches and crew time. Research is conducted in a wide variety of fields, including astrobiology, astronomy, physical sciences, materials science, space weather, meteorology, and human research including space medicine and the life sciences. Scientists on Earth have timely access to the data and can suggest experimental modifications to the crew. If follow-on experiments are necessary, the routinely scheduled launches of resupply craft allows new hardware to be launched with relative ease. Crews fly expeditions of several months' duration, providing approximately 160 person-hours per week of labour with a crew of six. However, a considerable amount of crew time is taken up by station maintenance.

Picture Credit : Google

Olympus Mons is the largest volcano in the solar system. The massive Martian mountain towers high above the surrounding plains of the red planet, and may be biding its time until the next eruption.

Found in the Tharsis Montes region near the Martian equator, Olympus Mons is one of a dozen large volcanoes, many of which are ten to a hundred times taller than their terrestrial counterparts. The tallest of them all towers 16 miles (25 kilometers) above the surrounding plains and stretches across 374 miles (624 km) — roughly the size of the state of Arizona.

In comparison, Hawaii's Mauna Loa, the tallest volcano on Earth, rises 6.3 miles (10 km) above the sea floor (but its peak is only 2.6 miles above sea level). The volume contained by Olympus Mons is about a hundred times that of Mauna Loa, and the Hawaiian island chain that houses the Earthly volcano could fit inside its Martian counterpart.

Olympus Mons rises three times higher than Earth's highest mountain, Mount Everest, whose peak is 5.5 miles above sea level. 

Credit : Space.com

Picture Credit : Google

It depends on which part of the space we are talking about. In general, it works like this: the closer to the stars, the higher the temperature. Another factor that weighs is the presence of matter: heat can be retained by it. As space becomes empty, temperature drops. In a vacuum (absence of matter), the temperature drops to 2.7 Kelvin or -270.45 Celsius. Only a few degrees above absolute zero (-273.15 °C).

There is no place colder than space. It has a lot of empty regions distant from heated bodies. The lowest temperature ever recorded on Earth was -89.2 ºC, in Antarctica. In interstellar space, where there is no absolute void (there are gases and dust grains), the temperature varies.

At the Earth’s thermosphere, where the atmosphere turns into space, the exact temperature can also vary substantially. However, the average temperature above 300 km is about 427 degrees Celsius at solar minimum and 927 degrees Celsius at solar maximum. But this does not mean that the space above the atmosphere is at this temperature. In fact, it is very cold. Only a body in this region that is illuminated by the sun can reach this temperature. In the dark areas of space, temperatures would drop a lot.

On the Moon, which has no atmosphere, temperatures vary a lot. When sunlight reaches the moon’s surface, the temperature can reach 127 degrees Celsius. However, when the sun goes down, temperatures can drop to – 173 degrees Celsius.

Credit : Curiosity Guide 

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In December 2018, NASA's Voyager 2 spacecraft reached interstellar space, following the example of its sister, Voyager 1. Right now, only five spacecraft have been launched capable of making such a grand exit, including the Voyagers. The remaining three are Pioneers 10 and 11, and New Horizons.

This milestone — reaching interstellar space — can be considered leaving the solar system by a certain definition. Let's be clear about what that entails. In 1990, the New York Times reported that Pioneer was reported to leave the solar system when it flew past Neptune's orbit. That's not what Voyager 2's scientists used to make their determination, however. Instead, the more recent measurements consider the crossing of the sun's heliopause, the theoretical boundary to its heliosphere, to be the determining factor for entering interstellar space. The heliosphere is a bubble of charged particles created by and flowing past the sun. Scientists use it to mark where interstellar space begins. 

But the heliosphere is tricky, and changes along with the sun's 22-year solar cycle, shrinking and growing with the solar wind, and stretching out behind the sun in the star's direction of travel. It's not something easily measured from Earth. NASA's Interstellar Boundary Explorer (IBEX) mission is working to remotely define the edges of the bubble.

Credit : Space.com

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The carbonaceous asteroids are abundant in the solar system (almost 75% of the known asteroids are of this type), especially on the edge of the asteroid belt between Mars and Jupiter (some astronomers say that another planet could have formed in that asteroid belt if Jupiter’s gravity wasn’t so massive, but now a possible planet lies in pieces in between Mars and Jupiter). 

As their name suggests, they are rich in carbon among other silicates and metals and are thus dark, which is why we might not have detected many more asteroids of this type in the outer reaches of our solar system. 

After the C-type asteroids, we have the S-type asteroids made of silicate and iron-nickel to be the next most abundant group in our system. They are very common on the inner edge of the asteroid belt and contribute 17% of the total asteroids in the entire system. 

With an albedo of 0.2, they are fairly bright and easier to see when we compare them to C-type asteroids. The largest in this group is 15 Eunomia at 205 miles or 330 km across that makes up 1% of the asteroid belt’s mass.

While the M-type asteroids are the third most common asteroid group, we don’t know much about their composition. They are located in the middle of the asteroid belt, and most if not all contain nickel and iron, but the subtler compositional characteristics depend on their distance from the Sun. 

Those close to it melted partially and basaltic lava oozed out onto the surface while those away from the Sun were able to hold on to their composition and structure.

The most massive asteroid in this group is the 16 Psyche with a diameter of 120 miles or 200 km.

Credit : Starlust

Picture Credit : Google