Mars lies much further from the Sun than Earth, so it doesn’t receive nearly as much heat. Additionally, its thin atmosphere enables solar radiation to quickly escape.
Due to this, temperatures change drastically from day to night on Mars, without its thermal blanket retaining heat energy for long.
Temperature
Mars, unlike Earth, has a thinner atmosphere. Without a blanket of air to hold in heat energy, its temperatures drop rapidly compared to Earth. Atmospheric conditions range from subzero (minus 153 degrees Celsius) at its poles during winter to around 75F (20C) on its equator during midday on summer.
Mars’ thin atmosphere contains approximately 95 percent carbon dioxide, leading to dust storms like those we experience here on Earth, which kick up particles into the sky, depositing it back onto Mars in fine particles that cover much of its surface – sometimes for weeks before being washed away by rainfall or rivers. At times it even snows on Mars! These carbon dioxide crystals resemble snowflakes a size comparable to red blood cells.
Even with its current frigid climate, some scientists speculate that Mars was once much hotter and wetter. According to them, early Mars may have been illuminated by a sun 25 percent dimmer than what exists now, allowing more solar energy absorption by its surface.
Though Mars may be too cold for water to remain liquid for extended periods of time, there is evidence of frozen polar ice sheets as well as subsurface sources. Scientists have also discovered evidence that water once flowed across its surface.
Mars averages an average surface temperature of -80 degrees Fahrenheit; its surface is significantly colder than Earth due to a thinner atmosphere, further from the sun, and an elliptical orbit that causes its seasons to vary more drastically than those on Earth.
As the Sun warms over time, Mars’ climate may transform. Polar ice caps and ground ice may melt, potentially opening crater lakes to more flooding, while CO2 in its atmosphere might diffuse upward resulting in further greenhouse warming and increasing surface temperatures.
Atmosphere
Mars’ atmosphere consists primarily of carbon dioxide with lower amounts of water vapor and nitrogen than found on Earth, creating an entirely unique composition compared to that on our home planet. Furthermore, atmospheric pressure on Mars is considerably lower, meaning gases react much more rapidly in response to energy input. Furthermore, gas concentration levels vary with season as sublimated ice accumulates and melts away, while exchanges occur with underground water tables.
Mars lies further from the Sun than Earth, which has an enormous effect on its climate. Temperatures on its surface may range anywhere between minus 140 and plus 80 Fahrenheit during summer in its northern and southern polar regions due to various sizes and locations of its polar ice caps.
Scientists currently hold two competing theories regarding why Mars’ atmosphere has become so thin. One theory holds that particles streaming from the Sun stripped gases away by evaporation – as investigated by NASA’s MAVEN mission. An alternative explanation could involve an impact causing rapid deflation such as that seen billions of years ago due to an impact with an object large enough.
Mars once had a thick enough atmosphere to support running water on its surface, as evidenced by orbital images showing vast river plains as well as observations by Mars rovers that suggest areas once covered with lakes or oceans.
Today, however, liquid water remains unstable across most of Earth. At its surface temperature is well below the triple point for liquid water; thus causing it to turn to vapor rather than freeze into solid ice. Some exceptions exist within crater basins such as Hellas Planitia where temperatures may have briefly exceeded this point.
Mars’ atmosphere is highly complex and fluctuates over time in its composition of gases. CO2 and hydrogen usually form close chemical bonds that make them relatively stable while oxygen and nitrogen have lower binding energies, increasing their likelihood of being transported by winds into other regions or towards the surface.
Humidity
Due to Mars being farther from its sun than Earth, its atmosphere is thinner. This allows its surface to heat and cool more rapidly, leading to large variations in temperature: temperatures on Mars range from minus 160 degrees Fahrenheit at the poles up to 70 degrees Fahrenheit during daytime hours.
Mars lacks an atmospheric blanket, meaning humidity levels are much lower than on Earth – only one hundredth as much water vapor exists, leading to colder, drier air with wider temperature differentials between daily high and low temperatures.
Mars is generally dusty and dry, though the planet does occasionally experience brief periods of surface water such as when rain falls upon its deserts; these instances, however, are few and far between. Mars’ primary source of moisture comes from water ice covering its polar caps – these caps consist of frozen carbon dioxide that gradually recede during summer days before reappearing again during winter nights.
Although water may exist on Mars, its stability as liquid remains limited due to atmospheric pressure often being lower than its triple point. However, certain features with an overlying layer of carbon dioxide may help trap liquid forms of it for use later.
This infographic compares temperatures at Mars’ Gale Crater to Los Angeles. It displays how much colder it is on Mars throughout the year and highlights differences in daily high and low temperatures more distinctly than on Earth.
NASA’s Curiosity rover arrived on Mars in 2012 at VL1 sol 95 (solar longitude of its landing site). This graphic shows data collected by this instrument during its mission. The vertical axis represents time; one sol equals one-twelfth of a year. The horizontal axis shows temperature; this particular graph has temperatures as low as minus 140 deg F for sol 95 at its top; red indicates winter and blue signifies summer season based on color-coding of graph. HUMICAP humidity sensors were used for plotting data, similar to what are used by vaccine labs, manufacturing facilities as well as museums to maintain works of art in peak condition.
Clouds
Mars’ atmosphere is comprised mostly of carbon dioxide, making it very difficult for temperatures to remain constant from day to night and leading to temperatures fluctuating dramatically day-by-day. There are also frequent dust storms that engulf much of its surface making visibility limited and visibility reduced.
Mars features several types of clouds, such as cirrus, fibrous and mesosphere. Cirrus clouds consist of small ice crystals forming in the polar regions and are typically white in colour; thicker fibrous clouds made up from water vapor make up fibrous clouds while the mesosphere clouds represent its highest level and are made of sulfates and sodium chloride with white hues.
Scientists have also discovered other forms of cloud formation on Mars, such as fog or ground haze and plumes, with their distinctive shapes. Fog usually forms during cooler times of day such as dawn and dusk and is also found in valleys and canyons. Plumes likely form from dust particles rising from Mars’ surface.
Mars hosts another type of cloud known as a cyclone, typically found in its northern polar regions and consisting of an outer layer and inner hole with approximately the same size eye, typically appearing around morning time before dissipating by afternoon; these clouds have even been known to appear each Martian year at approximately the same time.
Clouds are rare in Mars’ thin atmosphere, yet when they do appear they can be spectacular. NASA scientists recently noticed clouds on Mars that appeared earlier and higher than anticipated – likely made of ice crystals forming at high altitudes – which allowed researchers to gain more insights into its atmosphere and climate.