- 3879
- VENUS - our
sister planet? The “Mercury probe”
provided new info about Venus.“BepiColombo” and “Solar Orbiter” are also
helping us better understand Earth's sister planet. The two probes en route to the sun, recently
passed by Venus at nearly the same time, visiting Earth's sister planet within
a day of each other in August 2021.
----------------------- 3879
- VENUS - our
sister planet?
-
- BepiColombo
had a perfect view of the different regions within the magnetosheath and
magnetosphere. Earth's magnetic field
is a key reason why life has been so successful here. Magnetic fields help
deflect high-energy particles streaming from the sun, known as the solar wind,
protecting the fragile atmosphere of the planet. Venus doesn't have a magnetic
field created deep in its core like Earth does.
-
- However,
Venus does have something known as an "induced" magnetic field, in
which the solar wind interacts with charged particles in Venus' atmosphere to create
a magnetosphere surrounding the planet.
-
- Solar
Orbiter passed by Venus just outside this magnetosphere, observing the solar
wind in its calm, undisturbed state. At the same time, BepiColombo zipped
through the "stagnation region," the area where the solar wind and
atmosphere are expected to interact at Venus.
-
- Together,
the probes' observations provided experimental evidence that charged particles
are, in fact, slowed down by this region, protecting Venus' atmosphere from
erosion by the solar wind.
-
- This is
also an important finding for planets beyond our solar system, since
astronomers now know there is a way for exoplanets without an internal magnetic
field to retain their atmospheres like Venus has and therefore possibly even harbor
life.
-
- Venus is
still the hottest and brightest planet in the solar system. Venus' atmosphere traps heat from the sun as
an extreme version of the greenhouse effect that warms Earth. The temperature
on Venus are hot enough to melt lead.
-
- The
scorching planet is named after the Roman goddess of love and beauty and is the
only solar system planet named after a female.
In ancient Greek city-states, however, Venus was called Aphrodite.
-
------------------------------- VENUS FACTS:
-
----------------------- Length of day: 243 Earth days
-
----------------------- Length of year: 225 Earth days
-
----------------------- Distance from sun: 67 million miles
-
----------------------- Number of moons: 0
-
----------------------- Surface temperature: 900° F (480° C)
-
----------------------- Diameter: 7,520 miles (12,100 km)
-
--------------- Atmospheric composition: 96% carbon dioxide,
3% nitrogen.
-
- In ancient
times, Venus was often thought to be two different stars, the evening star and
the morning star, that is, the ones that first appeared at sunset and sunrise.
In Christian Latin, they were respectively known as Vesper and Lucifer. (In
Christian times, Lucifer, or "light-bringer," became known as the name
of Satan before his fall.)
-
- Venus is
highly visible from Earth due to its reflective clouds. In the sky, Venus
appears as a brilliant white object that is one of the brightest natural things
in the night sky. Its maximum magnitude, or apparent brightness, is close to
-5. By comparison, the moon is roughly
-14, The lower an object's magnitude, the brighter it appears to the eye.
-
- Up close
the color of Venus is "rusty", but not the kind of deep red rust one
would find on the planet Mars. Rather, pictures NASA and others have sent back
from Venus suggest a world with tinges of red, brown and yellow. That color
comes from the number of volcanic rocks dotting the surface, as Venus is a
highly active world.
-
- The
"real" color of Venus, however, is impossible to see from orbit due
to the sulfuric acid clouds surrounding the planet. Pictures of Venus are thus
only visible if an orbiting satellite has the ability to peer through the thick
clouds.
-
- For a human
explorer to see the surface, they would need to descend and to survive the
oven-like temperatures and high pressures present down there. That harsh
environment likely means that for now, we'll be using robotic explorers to look
at Venus for us.
-
- The orbit
of Venus lies along the ecliptic, which is the same pathway that the other
planets, the sun and the moon also take in our solar system. That's no
coincidence, as the ecliptic represents the "plane" or the
orientation of our solar system
-
- Venus and
Earth are often called twins because they are similar in size, mass, density,
composition and gravity. Venus is only a little bit smaller than our home
planet, with a mass of about 80% of Earth's.
-
- Venus is not
a gas planet, but a rocky planet. The interior of Venus is made of a metallic
iron core that's roughly 2,400 miles wide. Venus' molten rocky mantle is
roughly 1,200 miles thick. Venus' crust
is mostly basalt and is estimated to be 6 to 12 miles thick.
-
- Why Venus
is the hottest planet in the solar system is rather complicated. Although Venus
is not the planet closest to the sun, its dense atmosphere traps heat in a
runaway version of the greenhouse effect that we see firsthand on Earth with
global warming.
-
- Temperatures
on Venus reach 880 degrees Fahrenheit, which is more than hot enough to melt
lead. Spacecraft have survived only a few hours after landing on the planet
before being destroyed.
-
- With
scorching temperatures, Venus also has a hellish atmosphere, that consists
mainly of carbon dioxide with clouds of sulfuric acid and only trace amounts of
water. The atmosphere of Venus is heavier than that of any other planet,
leading to a surface pressure that's over 90 times that of Earth, similar to the pressure that exists 3,300
feet deep in the ocean.
-
- Venus'
surface is extremely dry. During the planet's evolution, ultraviolet rays from
the sun evaporated water quickly, keeping Venus in a prolonged molten state.
There is no liquid water on its surface today because the scorching heat
created by its ozone-filled atmosphere would cause water to immediately boil
away.
-
- Roughly
two-thirds of the Venusian surface is covered by flat, smooth plains that are
marred by thousands of volcanoes, some of which are still active today, ranging
from about 0.5 to 150 miles wide, with lava flows carving long, winding canals
that are up to more than 3,000 miles in
length.
-
- Six
mountainous regions make up about one-third of the Venusian surface. One
mountain range, called Maxwell, is about 540 miles long and reaches up to some
7 miles high, making it the highest
feature on the planet.
-
- Venus also
possesses several surface features that are unlike anything on Earth. Venus has coronae, or crowns, ring-like
structures that range from roughly 95 to 1,300 miles wide. Scientists believe
these formed when hot material beneath the planet's crust rose, warping the
planet's surface. Venus also has 'tesserae”, or tiles raised areas in which
many ridges and valleys have formed in different directions.
-
- Venus has
no known moons, which makes it nearly unique in our solar system. The only
other designated planet without moons is Mercury, which is quite close to the
sun.
-
- Venus takes
243 Earth days to rotate on its axis, which is by far the slowest of any of the
major planets. In fact, its day is longer than its year, and that may be due to
the thick atmosphere of Venus serving as a big brake on the planet's rotation.
And, because of this sluggish spin, its metal core cannot generate a magnetic
field similar to Earth's. The magnetic field of Venus is 0.000015 times that of
Earth's magnetic field.
-
------------------
Average distance from the sun: 67 million miles.
-
------------------
Perihelion (closest approach to the sun): 66,785,000 miles .
-
----------------
Aphelion (farthest distance from the sun): 67,692,000 miles .
-
- If viewed
from above, Venus rotates on its axis in a direction that's the opposite of
most planets'. That means on Venus, the sun would appear to rise in the west
and set in the east. On Earth, the sun appears to rise in the east and set in
the west.
-
- The
Venusian year, the time it takes to orbit the sun, is about 225 Earth days
long. Normally, that would mean that days on Venus would be longer than years.
However, because of Venus' curious retrograde rotation, the time from one
sunrise to the next is only about 117 Earth days long. The last time we saw
Venus transit in front of the sun was in 2012, and the next time will be in
2117.
-
- The very top layer of Venus' clouds zips
around the planet every four Earth days, propelled by hurricane-force winds
traveling roughly 224 mph. This superrotation of the planet's atmosphere, some
60 times faster than Venus itself rotates, might be one of Venus' biggest
mysteries.
-
- The clouds
also carry signs of meteorological events known as gravity waves, caused when
winds blow over geological features, causing rises and falls in the layers of
air. The winds at the planet's surface are much slower, estimated to be just a
few miles per hour.
-
- Unusual
stripes in the upper clouds of Venus are dubbed "blue absorbers" or
"ultraviolet absorbers" because they strongly absorb light in the
blue and ultraviolet wavelengths. These are soaking up a huge amount of energy,
nearly half of the total solar energy the planet absorbs.
-
- The Venus
Express spacecraft, a European Space Agency mission that operated between 2005
and 2014, found evidence of lightning on the planet, which formed within clouds
of sulfuric acid, unlike Earth's lightning, which forms in clouds of water.
Venus' lightning is unique in the solar system. It is of particular interest to
scientists because it's possible that electrical discharges from lightning
could help form the molecules needed to jumpstart life, which is what some
scientists believe happened on Earth.
-
- The United
States, Soviet Union, European Space Agency and Japan Aerospace Exploration
Agency have deployed many spacecraft to Venus, more than 20 so far. NASA's
Mariner 2 came within 21,600 miles of Venus in 1962, making it the first planet
to be observed by a passing spacecraft.
-
- The Soviet
Union's Venera 7 was the first spacecraft to land on another planet, having
landed on Venus in December 1970. Venera 9 returned the first photographs of
the Venusian surface. The first Venusian orbiter, NASA's Magellan, generated
maps of 98% of the planet's surface, showing features as small as 330 feet
across.
-
- The
European Space Agency's Venus Express spent eight years in orbit around Venus
with a large variety of instruments and confirmed the presence of lightning
there. In August 2014, as the satellite began wrapping up its mission,
controllers engaged in a month-long maneuver that plunged the spacecraft into the
outer layers of the planet's atmosphere.
-
- Venus
Express survived the daring journey, then moved into a higher orbit, where it
spent several months. By December 2014, the spacecraft ran out of propellant
and eventually burned up in Venus' atmosphere.
-
- Japan's
Akatsuki mission launched to Venus in 2010, but the spacecraft's main engine
died during a pivotal orbit-insertion burn, sending the craft hurtling into
space. Using smaller thrusters, the Japanese team successfully performed a burn
to correct the spacecraft's course.
-
- A
subsequent burn in November 2015 put Akatsuki into orbit around the planet. In
2017, Akatsuki spotted another huge "gravity wave" in Venus'
atmosphere. The spacecraft still orbits Venus to this day, 2023, studying the
planet's weather patterns and searching for active volcanoes.
-
- In 2021,
NASA announced two new missions to Venus that will launch by 2030. The agency announced on June 2, 2021, that
they will be sending missions DAVINCI+ and VERITAS, chosen from a shortlist of
four spacecraft, for the next round of Discovery missions to Venus.
-
- DAVINCI
(Deep Atmosphere Venus Investigation of Noble Gases, Chemistry and Imaging)
will dive through the planet's atmosphere, studying how it changes over time.
-
- VERITAS
(Venus Emissivity, Radio Science, InSAR, Topography and Spectroscopy) will map
the planet's surface from its orbit using radar.
-
- While
destinations in our solar system like the moons Enceladus or Titan or even
planet Mars are currently the go-to spots to search for signs of
extraterrestrial life. But a
breakthrough scientific discovery in 2020 suddenly had scientists discussing
whether or not it was possible that life could somehow exist in the present-day
hellish atmospheres of Venus.
-
- In 2020,
scientists revealed the discovery of a strange chemical in the planet's clouds
that some think could be a sign of life: phosphine. Phosphine is a chemical
compound that has been seen on Earth as well as on Jupiter and Saturn.
Scientists think that, on Venus, it could appear as it does on Earth, for very
short amounts of time in the planet's atmosphere.
-
- But what
does this phosphine discovery have to do with the search for life? While phosphine exists in strange ways such
as rat poison, it has also been spotted alongside groups of certain
microorganisms and some scientists think that, on Earth, the compound is
produced by microbes as they decay chemically.
-
- This has
caused some to suspect that, if microbes could create phosphine, then perhaps
microbes might be responsible for the phosphine in Venus' atmosphere. Since the
discovery, there have been follow-up analyses that have made some doubt whether
or not the compound is created by microbes, but scientists are continuing to
investigate, especially with new missions planned for the planet.
-
February
16, 2023
3879
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