What Are the Planets Mercury and Venus?
Mercury and Venus are the innermost planets and often appear before or after the Sun in the sky, shining brightly due to their thick atmospheres.
Venus suffers because its solar energy is quickly converted to heat that radiates back out as light, making escape difficult. Furthermore, there are few old craters and no evidence of plate tectonics like on the Moon.
1. It’s the closest planet to the Sun
Mercury is the smallest planet in our Solar System and orbits our Sun fastest of any other. A full orbit takes just 88 days! As it lies so close to its star, Mercury becomes much hotter than any of the other rocky planets found within the system.
Scientists are exploring Mercury to gain more knowledge about rocky planets that orbit close to their star, and may provide clues as to the formation of our Solar System. Furthermore, Mercury is easily visible with an 8 cm (3.1 in) telescope during broad daylight viewing or evening skies when at its greatest elongation from the Sun; just be careful not to block your view!
Mercury stands out among our Solar System planets by not being tidally locked with the Sun; meaning one side always faces towards it while its opposite never does. Due to this feature, mercury does not experience seasonal changes like Earth does but does have an eccentric orbit which means sunlight reaches different areas throughout the year.
At some longitudes, the Sun would rise rapidly before setting quickly; at others, however, it would rise slowly before staying visible for an extended period before returning back into darkness again – this being caused by Mercury’s orbit and its eccentricity.
Given these considerations, life is unlikely to ever exist on Mercury due to its proximity to the Sun, extreme heat levels and thin atmosphere. Scientists hope to learn more about rocky planets like Mercury and Venus by sending spacecraft. One such mission, Messenger, will eventually orbit around Mercury before mapping its entire surface in high resolution – scheduled to arrive by 2011.
2. It’s the brightest planet in the sky
As our nearest planet, Pluto is easily the brightest object in our sky and most reflective rocky planet in our Solar System – even outshone by gas giants. However, its thick carbon dioxide atmosphere reaches scorching temperatures which results in scorching heat temperatures that even eclipse those seen by gas giants!
Mars stands out from its solar neighbors by virtue of its intense heat and reflective clouds, appearing like a glowing ball of fire. Its phases can also be observed through a telescope; Galileo first observed these beauties early in the 17th century; this observation helped galvanize his support for sun-centered “heliocentric” models which placed Venus closer to Earth than to Sun.
Mercury orbits so close to that of the Sun that it passes very quickly across the sky in just hours, making its passage only visible during a limited window each year. Mercury’s brightness depends on how close it is to the Sun and which phase it is in; best seen near horizon in evening and morning hours during March-April evenings or September-October mornings respectively (both times for Northern Hemisphere viewings).
Mercury’s magnetic field is far weaker than Earth due to its closeness to the Sun, yet a magnetosphere forms around its planet, channeling plasma from the sun down toward its surface and trapping neutrally charged hydrogen and helium particles into a thin exosphere. Magnetic tornadoes generated from such events can create powerful electromagnetic storms capable of destabilizing spacecraft or even leading to their crash.
Mars’ rocky core generates an iron-rich magnetic field approximately one percent as strong as Earth’s. Measurements made by MESSENGER show how this field interacts with solar wind in surprising ways, tugging low-orbit spacecraft around and making navigation challenging.
NASA has funded several early-stage mission concepts to explore Venus in the coming decades, including an experimental “steampunk” rover using levers instead of electronics (which might burn out) and an airship balloon capable of exploring from lower altitudes.
3. It’s the closest planet to Mercury
Mercury is our closest planet in terms of distance; its elliptical orbit brings it close to both Earth and Mars and Venus. Mercury orbits our Sun every 88 days – the fastest rate among all planets within our Solar System!
Notably, however, Mercury doesn’t always remain Earth’s nearest planet on a consistent basis; this depends on where and when Mercury is on its orbital path and year. At certain points during its year cycle, Venus can actually come much closer due to its longer orbital period spending some time opposite of Earth from where we exist on the Sun’s side of our solar system.
Even so, Mercury remains closer to Earth than Venus is on average. These inner planets formed at roughly the same time from condensing nebula some 4.5 billion years ago; but their similarities end there – Venus has an exceptionally thick atmosphere which increases surface temperatures significantly more than Mercury; furthermore it lacks any surface water; there may even be evidence for possible pockets of ice at its poles.
Mercury lacks an atmosphere to warm its surface and therefore remains extremely cold, yet does have an exosphere composed of atoms blasted off by solar wind and meteoroids, drawn toward Mercury’s magnetic field and then funneling onto its surface, where their presence causes intense magnetospheres that funnel fast-moving plasma back towards its planet surface.
Magnetic activity gives rise to bright streaks known as “crater rays.” These streaks of light reflect off crushed rocks that reflect light back into space; when looking at Mercury craters you are actually witnessing the trail of these shining rays.
Mercury may seem closer to Earth than Mars and Venus, but due to its tiny orbit it also comes closer to Jupiter, Saturn, Uranus, and Neptune than to our home planet! In fact, Jupiter could even be considered closer than Mercury!
4. It’s the closest planet to the Moon
Mercury, our closest planet and also one of our least visible ones, can often be difficult to spot without using a telescope. Because its orbit so closely orbits around the Sun, Mercury can appear either early morning or late at night – making it hard for even experienced stargazers to locate without one. Plus, as its speed around our Sun exceeds 106,000 miles per hour it was no wonder Roman astronomers associated it with messenger god Mercury himself!
Mercury can often resemble our Moon. That’s because both planets share similar composition: a dense core surrounded by thick mantle and thin crust, with Mercury having an even more cratered surface than our Moon due to violent past events. Mercury lacks an atmosphere, yet has an impressively complex magnetic field capable of funneling fast solar wind plasma down onto its surface and producing intense magnetic storms that launch neutrally charged atoms high into space.
Mercury’s surface is littered with bright streaks known as crater rays, created when an asteroid or comet impacts it and digs a large hole, crushing large volumes of rock into fine particles that reflect more light, making the crater rays appear brighter at first but gradually dimming with space pollution over time.
Mercury boasts other intriguing characteristics. For instance, its polar regions contain water ice in craters that rarely see sunlight – an unusual feature among rocky planets, which typically experience warmer temperatures all across their surfaces. Scientists study Mercury to gain more knowledge of rocky planets across space – especially those close to their stars.
Mercury can best be observed by looking out for it in the evening sky. Right now, Mercury is slowly climbing through western twilight towards its greatest elongation on November 15; look out for Jupiter nearby as well.