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Planetary Science
Planetary Science is the study of Planets and the Solar System, a combination of Astronomy and Earth Sciences. Find questions about the different planets and more.
25,144 Questions
What satellite is the largest relative to the size of its planet?
Ganymede, one of Jupiter's moons, is the largest moon in the solar system and is even larger than the planet Mercury. It has a diameter that is about 0.41 times that of Earth's moon.
Where is the largest gap between planets?
No. It is Mars and Jupiter. It is the biggest gap due to the asteroid belt
What is the exact length of one year?
It depends on exactly what you mean by "year" and it also varies over time, so there is no single exact answer.
The short answer is either approximately 365.24218967days long (365 days, 5 hours, 48 minutes and 45.1875 seconds) on average, or approximately365.256363051 days (365 days, 6 hours, 9 minutes and 9.7676 seconds) in the year 2000, but changing slightly every year.
All scientific definitions of a "year" for our earth are within about 25 minutes of each other, but vary based on what you measure against. Everything in the universe is constantly moving relative to everything else, so there is no absolutely fixed frame of reference to measure anything against. All measurements are relative to something you choose to measure against and are only valid for the period in time in which you took the measurement. Measurements are also only accurate to the precision you can attain with the measuring equipment you use. It is impossible to measure anything with infinite precision. Every measurement is an approximation with some limited precision over a period of time where what you are measuring is constantly changing, however infinitesimally. At best you can only measure an approximate range between some limits. On top of that a "year" can be measured many different ways.
A "Tropical Year" uses the earth's tilted axis and equatorial plane to gauge the time it takes for the earth to complete one kind of cycle around the sun we call a "year". Over the course of a year as the earth orbits the sun, the earth's axis and equator change their orientation relative to the sun, cycling back roughly to the starting point once every "Tropical Year". Over these repeating yearly cycles, days and nights get longer and shorter in the northern and southern hemispheres for half of a year and then reverse back the other direction for the other half of a year. This is one primary way measure a year.
A "Tropical Year" in recent times is approximately 365.24218967 days long (365 days, 5 hours, 48 minutes and 45.1875 seconds) on average over all equatorial points. This time changes slightly from one year to the next, depends on exactly what equatorial point you are measuring the cycle of and is influenced slightly by so many factors that constantly change that we will probably never be able to predict precisely how long a "Tropical Year" thousands of years in the future will be. That far out, things could change by many seconds compared to what we do our best to estimate or predict due to tiny effects of interactions with meteors and asteroids and other things that we can not possibly predict and account for.
A "Calendar Year" is exactly 365.2425 days long (365 days, 5 hours, 49 minutes and 12 seconds) on average over any 400 year period. A year is exactly 365 days on non-leap years and 366 days long on leap years and we declare 97 of every 400 years to be a leap year. That's one in four minus one in 100 plus one in every 400 years. This is the only exact length you can cite because we define the calendar year precisely this way as opposed to measuring what actually physically happens. All other measured years can only be approximated and will always be at least slightly different from one year to the next. Even if two measured years were exactly the same, we'd never know it for sure. We'd know they were at least very, very close, but we could not know that they were the same or exactly how close they were if they were ever so slightly different by less than our ability to measure.
A "Sidereal Year" is the time it takes for the earth to orbit the sun relative to the distant stars which are not stationary, but the closest thing to stationary we can measure against so far, due to their great distance and relatively slow movement in space. The "Sidereal Year" in the year 2000 was approximately 365.256363051 days (365 days, 6 hours, 9 minutes and 9.7676 seconds).
The seasonal changes we experience each year as the earth orbits the sun are due largely to the earth's axis tilting the northern and southern hemispheres toward and away from the sun over the course of a "Tropical Year". This "Tropical Year" is what our calendar attempts to approximate by interjecting an extra day on leap years so that winter and summer occur at roughly the same time of year, year after year. If our calendar approximated the "Sidereal Year" instead of the "Tropical Year", winter and summer would slowly shift earlier and earlier in the year over time.
The severity of the earth's summers and winters also fluctuate over time partly due to the earth's orbit being elliptical. Our elliptical orbit brings us closest to the sun at one point during an "Anomalistic Year" and farthest away from the sun at another point in our orbit a half of an "Anomalistic Year" later.
An "Anomalistic Year" is approximately 365.259635864 days long (365 days, 6 hours, 13 minutes and 52.5386 seconds), slightly longer than the "Tropical Year". Because these things are not in sync with each other the distance at any given time of the "Tropical Year", such as winter or summer in the northern or Southern Hemisphere, from the earth to the sun becomes closer or farther from one year to the next and then eventually cycle back to roughly the same distance about every 21,000 years give or take a lot since all of these things are constantly changing a little.
Except in leap years 352 years but in leap years 353
What does the terrestrial megafauna means?
Terrestrial megafauna refers to large animals that live on land, such as elephants, rhinos, and big cats. These animals play crucial roles in their ecosystems and their conservation is important for maintaining biodiversity. They are often at risk due to habitat loss and poaching.
What planet has the warmest planet cloudy planet?
Venus is the warmest planet in our solar system because of its thick atmosphere that traps heat. It is also very cloudy, with a dense layer of clouds made of sulfuric acid that contribute to its extreme greenhouse effect, keeping the planet hot.
As I write this on August 25, 2012, Mars and Saturn are clearly visible just above the western horizon at sunset. Venus is the "Morning Star", and is the brightest thing in the sky in the eastern sky just before dawn. Jupiter rises about 1AM, and is visible until dawn.
Mercury is tougher; it's currently too close to the Sun to be visible and is headed to a "superior conjunction" when Mercury will be on the other side of the Sun from us in mid-September. It will remain too close to the Sun to be visible until the end of October. By Halloween, you should have a chance to see Mercury low in the western sky just after sunset.
What are the two reasons why earth have different length of days?
The two main reasons for Earth having different lengths of days are its axial tilt and elliptical orbit. The tilt of Earth's axis causes the angle at which sunlight hits different parts of the planet to vary throughout the year, affecting the length of daylight hours. Additionally, Earth's elliptical orbit means its distance from the sun changes, altering the speed at which the planet rotates on its axis.
What is an object at a distance of 68 AU from the Earth?
All objects orbiting the Sun do so in an elliptical orbit. Therefore sometimes they are further away while at others they are closer.
To be 68 AU from the Earth you would need to know the position of the Earth relative to the said object as the Earth could be on the other side of the Sun.
The closest objects to 68 AU from the Sun would be Eris or 2007 OR10.
- Eris: Aphelion 97.56 AU Perihelion 37.77 AU Semi major axis (Average) 67.67 AU
- 2007 OR10: Aphelion 100.79 AU Perihelion 33.62 AU Semi major axis (Average) 67.21 AU
How long does it take mars to axis?
It takes any planet one day to rotate on its axis. A Martian day is only slightly longer than an Earth day: 24 hrs. 39 mins. 35 secs.
What would happened if there was no sun on earth?
Without the sun, the Earth would lose its primary source of energy and warmth. This would cause temperatures to drop drastically, leading to freezing conditions and making it impossible for most life forms to survive. Additionally, photosynthesis, which is vital for plants and oxygen production, would cease, ultimately leading to the collapse of entire ecosystems.
What size is mars largest or smallest?
Mars has a diameter of about 6,779 kilometers, making it smaller than Earth. Its largest volcano, Olympus Mons, has a diameter of around 624 kilometers, while the smallest features on Mars can be as small as a few meters.
What keeps the sun in the same place?
The sun is held in place by its own gravity, which is balanced by the outward force of the nuclear fusion reactions happening in its core. This dynamic equilibrium keeps the sun stable and prevents it from collapsing or drifting away.
What are the sizes of all 8 planets?
- Mercury: 5000 Km
- Venus: 12 000 Km
- Earth: 12 800 Km
- Mars: 7000 Km
- Jupiter: 140 000 Km
- Saturn: 120 000 Km
- Uranus: 52 000 Km
- Neptune: 50 000 Km
How big is a star compared to the earth?
Stars are significantly larger than Earth. For example, the Sun's diameter is about 109 times that of Earth. Larger stars, such as Betelgeuse, can be hundreds or even thousands of times larger than the Sun.
Why are the new planets called Kepler?
The new planets are named after the Kepler Space Telescope, which was a NASA mission that searched for exoplanets using the transit method. The telescope discovered thousands of exoplanets during its mission.
How do you fit up eccentric reducer?
To install an eccentric reducer, align the top flat side of the reducer with the upper pipe, ensuring that the bottom side is offset from the centerline of the lower pipe. Once aligned, weld or connect the reducer to the pipes using the appropriate method for the specific material being used. Finally, inspect the installation for proper alignment and seal before putting the system into operation.
Why doesn't a star expand or collapse during the main sequence?
A star maintains equilibrium during the main sequence because the inward force of gravity is balanced by the outward pressure from nuclear fusion in its core. This balance between gravity and radiation pressure prevents the star from collapsing or expanding significantly during this phase.
How can you calculate how many manhole rings to use to reach cover levels?
To calculate the number of manhole rings needed to reach cover levels, you first need to determine the desired cover level. Then, measure the height of each manhole ring and divide the desired cover level by this measurement to find the number of rings required. Round up to the nearest whole number to ensure proper cover level.
How many suns fit between the earth and the sun?
The Earths orbital distance from the sun is 149,597,890km (92,955,820 miles) on average, enough to fit 107 more suns between the suns surface and Earth.
Why do the the patterns of the stars appear to shift westward slightly from night to night?
The apparent westward shift of star patterns from night to night is due to Earth's rotation on its axis. As Earth rotates, the position of an observer on the planet changes in relation to the stars, causing them to appear to move across the sky in an eastward direction. This movement creates the illusion of stars shifting westward in the night sky.
A woman more beautiful than the one I love? The sun itself has never seen anyone as beautiful since the world began.
What are the effects of earths rotation on humans?
It causes day and night, which effects many things, because the Sun gives energy. For humans, solar electricity cannot be produced. They do not have extraordinary eye sight and so daily activities can not be performed as well. Humans also need rest and therefore become dormant at night. Plants need the Sun for food. They have a chemical in them called chlorophyll which is used in photosynthesis. They need the Sun's light to perform this. Reptiles, amphibians and others animals (not birds or mammals) rely on the Sun for energy as they are cold blooded and can not control their core temperature. They therefore need the Sun to gain energy and only move about in the day. Overall, the Earth's rotation has many effects on animals, plants and humans, especially on their energy levels and performance.
What planet is 1 10th of the distance Uranus is from the sun?
Uranus is around 19 AU from the sun, theres no planet that is 1.9 AU from the sun. the closest to this is Mars, at 1.5 AU.
