If asked by an average person which planet was closest to Earth, most would likely say Venus. After all, Venus comes before Mars chronologically and has an orbit that aligns it closely with most other planets in our Solar System.
But is that true? A recent study suggests Mercury as being closer than all the others.
Venus
Venus, commonly referred to as Earth’s sister planet, can appear idyllic until you get closer; then its hellish surface comes into focus: carbon dioxide fills its atmosphere, hot enough to melt lead; air pressure exceeds 90 times what would be experienced if one were to jump into an ocean on Earth; greenhouse effect traps the Sun’s heat; the planet has crushing air pressure of over 90 times what one would experience diving underwater here on Earth! Venus also suffers from runaway greenhouse effect caused by carbon dioxide and other chemicals trapping Sun-heat in an effort to control climate control measures that otherwise.
Venus is the hottest planet in our Solar System despite being farthest away. It features a surface covered in rust-colored mountains and thousands of volcanoes; scientists believe some may still be active today. Unfortunately, Venus’ thick atmosphere filled with toxic carbon dioxide prevents life from taking root anywhere on its surface; but missions to Venus have revealed it once had liquid water sources.
As most of us were taught, if you look at the planets in ascending order it may appear that Venus is closest to Earth; however, that’s technically incorrect as their elliptical orbits mean they only cross each other at certain intervals for limited periods.
Mercury actually becomes the closest planet to Earth due to these fluctuations; something which had long perplexed people but is easy to comprehend when taken into account when considering how the planets move.
Education about space physics, such as its distance between planets, is of vital importance for children’s wellbeing. The free All About Venus PowerPoint presentation offers a great way for kids to learn all about Earth’s nearest neighbor including its high temperatures, dense atmosphere and why it was named after Roman goddess of love and beauty Venus. Plus it includes a fact sheet you can print as a poster to decorate any learning environment!
Mars
Mars is the fourth planet from the Sun and typically, Earth’s closest neighbour. Being red makes Mars easily identifiable in the night sky; its closest approach will occur around January 2025.
At first glance, Venus seems like the closest planet to Earth; however, this is not accurate. To qualify as our closest neighboring planet, a planet’s orbit must align directly with that of Earth every 10,000 years or so; Mars can even sometimes come closer during certain points in its journey around us than Venus does when at its closest point in its orbit.
At this stage, the planet reaches its perihelion – or closest point to the Sun and atmosphere thick enough to trap much heat – making it appear much warmer than it really is. Over time however, solar radiation has stripped away much of Mars’ original atmosphere; today its atmosphere consists mostly of carbon dioxide with minor amounts of nitrogen and argon present – an environment which traps very little heat making this place extremely cold!
Astronomers have used computer simulations to calculate the relative proximity between various planets and Earth and have found that Mercury is actually closer than Venus to our home planet, taking into account both distance between orbital points as well as differences in size between them. Mercury tends to stay closer on average than Venus despite having more time spent away from our home world than vice versa.
Although Mars is one of the closest rocky planets to Earth, reaching it would still take quite some time for any spacecraft. How long it would take depends on both where each planet lies in its orbit and what the spacecraft wants to accomplish when arriving there – for instance if just passing by is desired then straight-line travel may suffice, while orbital or landing missions on Mars require much longer journeys with more complicated curves that could last months before arriving there.
Mercury
Mercury, our closest planet in terms of distance to the Sun, and one of the smallest in our solar system – just slightly larger than Earth – is one of our closest neighbours in terms of size as well. Pockmarked with craters, its atmosphere thin and temperatures hot enough to melt lead, the side facing directly towards the Sun can experience temperatures hot enough for lead melting, while shaded areas experience temperatures not much below the freezing point of water.
Mercury orbits the Sun every 88 days while Venus requires 225 to complete her orbit around it. Because of this difference in duration between them, when asked which planet is closer to Earth they usually respond with Venus; though keep in mind this order could change at any time and that Venus may soon overtake Mercury in terms of proximity to our home planet.
There is an easy explanation for this phenomenon. Planets are ranked according to their distance from the Sun at any given time, which means that planets nearer the Sun have shorter orbital periods and smaller radii, thus appearing closer to Earth than distant planets with longer cycles and larger radius.
Though Earth and its planets may seem distant to people on the outside looking in, most people still struggle to identify which is closer. This is usually due to people relying on a simplistic formula which only considers their current rank order from Earth – this method does not accurately account for changes that happen over time in terms of rank order of planets as seen from Earth. Many astronomers have discovered this can cause inaccurate calculations.
The easiest solution to this issue is using more accurate calculations of distance between planets. A technique known as point-circle method averages the distances between points on each planet’s orbit while taking time into consideration, which has shown that on average Mercury is closer to our solar system than Venus – in fact it is closest of all seven planets!
The Moon
The Moon is our natural satellite and has much to offer us. Though only fifth in size among the planets in our solar system, it only weighs one-fourth as much. Made of mostly rock with surface pitted with thousands of meteorite impacts over billions of years known as craters; bright light from its sunlit side illuminates it brightly; its reflectivity (only slightly better than worn asphalt), and gravity help control ocean tides, body tides, and daily lengthening processes on Earth.
The Moon’s distance from Earth does not remain constant; rather, it follows an elliptical orbit around our planet with perigee (its closest approach) occurring once every 27 days and at its farthest point from us (apogee), about 252,000 miles. On average however, its average distance to us is 238,860 miles – equivalent to about 30 Earth diameters.
Mercury or Venus might currently be considered our closest planet; however, that could change at any moment. A 2019 commentary in Physics Today highlighted an incorrect way popular science writers use for calculating planetary distances; often using an incorrect formula that subtracts only average distance between planets from each other but does not account for changing speeds and positions of both planets. Researchers devised a new method which took both distance and time into account; their model showed that over a 10,000 year period Mercury is closer than Venus was and also that in general Mercury is closer than Venus to all other planets on average than Venus is.
But the answer to this question is more complex than one might assume; planets’ orbits do not follow perfect circles and some planets such as Mars can come closer to the Sun than Venus at certain times of year. Meanwhile, although not currently the closest planet to Earth, Moon is steadily approaching. Currently it is in its last quarter phase where half its Northern Hemisphere surface area has illumination.