So NASA Won The Internet Today…

Sequence of Venus atmosphere images taken by the Venus Monitoring Camera (VMC) during the Venus Express orbit in July 2007. The view shows the southern hemisphere of the planet.

Credit: ESA/MPS/DLR/IDA

I’ve finally got round to continuing with my series of photos about the planets of the solar system! Next on my list is Venus. Venus is the second closest planet to our home star and notable for many strange oddities. For example, it has a rotational period of 243 days, whilst a year takes just 225 days. It has a diameter of ~12100km, making it very similar in size to Earth. It is often compared to Earth as its so-called twin planet, which may be true for aspects such as mass, size and proximity to the sun, but for almost everything else, they are vastly different.

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Wind hitting Venus’s mountains makes the planet rotate faster

Turbulent atmosphere speeds Venus’s days by a full 2 minutes

Venusian mountains impact its rotation

Ten interesting facts about Mars

The ancient Sumerians believed that Mars was Nergal, the god of war and plague. During Sumerian times, Nergal was a minor deity of little significance, but, during later times, his main cult center was the city of Nineveh. In Mesopotamian texts, Mars is referred to as the “star of judgement of the fate of the dead”. The existence of Mars as a wandering object in the night sky was recorded by the ancient Egyptian astronomers and, by 1534 BCE, they were familiar with the retrograde motion of the planet. By the period of the Neo-Babylonian Empire, the Babylonian astronomers were making regular records of the positions of the planets and systematic observations of their behavior. For Mars, they knew that the planet made 37 synodic periods, or 42 circuits of the zodiac, every 79 years. They invented arithmetic methods for making minor corrections to the predicted positions of the planets.

Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System after Mercury.

The bright rust color Mars is known for is due to iron-rich minerals in its regolith — the loose dust and rock covering its surface. The soil of Earth is a kind of regolith, albeit one loaded with organic content. According to NASA, the iron minerals oxidize, or rust, causing the soil to look red.

The rotational period and seasonal cycles of Mars are likewise similar to those of Earth, as is the tilt that produces the seasons. Mars is the site of Olympus Mons, the largest volcano and second-highest known mountain in the Solar System, and of Valles Marineris, one of the largest canyons in the Solar System.

Mars has two moons, Phobos and Deimos, which are small and irregularly shaped. These may be captured asteroids, similar to 5261 Eureka, a Mars trojan.

There are ongoing investigations assessing the past habitability potential of Mars, as well as the possibility of extant life. Future astrobiology missions are planned, including the Mars 2020 and ExoMars rovers. Liquid water cannot exist on the surface of Mars due to low atmospheric pressure, which is less than 1% of the Earth’s, except at the lowest elevations for short periods. The two polar ice caps appear to be made largely of water. The volume of water ice in the south polar ice cap, if melted, would be sufficient to cover the entire planetary surface to a depth of 11 meters (36 ft). In November 2016, NASA reported finding a large amount of underground ice in the Utopia Planitia region of Mars. The volume of water detected has been estimated to be equivalent to the volume of water in Lake Superior.

Mars can easily be seen from Earth with the naked eye, as can its reddish coloring. Its apparent magnitude reaches −2.91, which is surpassed only by Jupiter, Venus, the Moon, and the Sun. Optical ground-based telescopes are typically limited to resolving features about 300 kilometers (190 mi) across when Earth and Mars are closest because of Earth’s atmosphere.

Like Earth, Mars has differentiated into a dense metallic core overlaid by less dense materials. Current models of its interior imply a core with a radius of about 1,794 ± 65 kilometers (1,115 ± 40 mi), consisting primarily of iron and nickel with about 16–17% sulfur. This iron(II) sulfide core is thought to be twice as rich in lighter elements as Earth’s. The core is surrounded by a silicate mantle that formed many of the tectonic and volcanic features on the planet, but it appears to be dormant. Besides silicon and oxygen, the most abundant elements in the Martian crust are iron, magnesium, aluminum, calcium, and potassium. The average thickness of the planet’s crust is about 50 km (31 mi), with a maximum thickness of 125 km (78 mi). Earth’s crust averages 40 km (25 mi).

Mars lost its magnetosphere 4 billion years ago, possibly because of numerous asteroid strikes, so the solar wind interacts directly with the Martian ionosphere, lowering the atmospheric density by stripping away atoms from the outer layer. Both Mars Global Surveyor and Mars Expresshave detected ionised atmospheric particles trailing off into space behind Mars, and this atmospheric loss is being studied by the MAVEN orbiter. Compared to Earth, the atmosphere of Mars is quite rarefied.

Mars’s average distance from the Sun is roughly 230 million kilometres (143,000,000 mi), and its orbital period is 687 (Earth) days. The solar day (or sol) on Mars is only slightly longer than an Earth day: 24 hours, 39 minutes, and 35.244 seconds. A Martian year is equal to 1.8809 Earth years, or 1 year, 320 days, and 18.2 hours

Mars is scarred by a number of impact craters: a total of 43,000 craters with a diameter of 5 km (3.1 mi) or greater have been found. The largest confirmed of these is the Hellas impact basin, a light albedo feature clearly visible from Earth. Due to the smaller mass of Mars, the probability of an object colliding with the planet is about half that of Earth. Mars is located closer to the asteroid belt, so it has an increased chance of being struck by materials from that source. Mars is more likely to be struck by short-period comets, i.e., those that lie within the orbit of Jupiter. In spite of this, there are far fewer craters on Mars compared with the Moon, because the atmosphere of Mars provides protection against small meteors and surface modifying processes have erased some craters.

Martian craters can have a morphology that suggests the ground became wet after the meteor impacted.

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images: NASA/JPL-Caltech/Univ. of Arizona , ESA, Tunç Tezel

astronomy facts

Ten Interesting facts about Venus

As one of the brightest objects in the sky, Venus has been a major fixture in human culture for as long as records have existed. It has been made sacred to gods of many cultures, and has been a prime inspiration for writers and poets as the “morning star” and “evening star”. Venus was the first planet to have its motions plotted across the sky, as early as the second millennium BC.

Venus is the second planet from the Sun, orbiting it every 224.7 Earth days. It has the longest rotation period (243 days) of any planet in the Solar System and rotates in the opposite direction to most other planets.

It does not have any natural satellites. It is named after the Roman goddess of love and beauty.

It is the second-brightest natural object in the night sky after the Moon, reaching an apparent magnitude of −4.6 – bright enough to cast shadows at night and, rarely, visible to the naked eye in broad daylight.

Venus is a terrestrial planet and is sometimes called Earth’s “sister planet” because of their similar size, mass, proximity to the Sun, and bulk composition.

It is radically different from Earth in other respects. It has the densest atmosphere of the four terrestrial planets, consisting of more than 96% carbon dioxide. The atmospheric pressure at the planet’s surface is 92 times that of Earth, or roughly the pressure found 900 m (3,000 ft) underwater on Earth. Venus is by far the hottest planet in the Solar System, with a mean surface temperature of 735 K (462 °C; 863 °F), even though Mercury is closer to the Sun.

As the closest planet to Earth, Venus has been a prime target for early interplanetary exploration. It was the first planet beyond Earth visited by a spacecraft (Mariner 2 in 1962), and the first to be successfully landed on (by Venera 7 in 1970). Venus’s thick clouds render observation of its surface impossible in visible light, and the first detailed maps did not emerge until the arrival of the Magellan orbiter in 1991. Plans have been proposed for rovers or more complex missions, but they are hindered by Venus’s hostile surface conditions.

Much of the Venusian surface appears to have been shaped by volcanic activity. Venus has several times as many volcanoes as Earth, and it has 167 large volcanoes that are over 100 km (62 mi) across. The only volcanic complex of this size on Earth is the Big Island of Hawaii. This is not because Venus is more volcanically active than Earth, but because its crust is older. Earth’s oceanic crust is continually recycled by subduction at the boundaries of tectonic plates, and has an average age of about 100 million years, whereas the Venusian surface is estimated to be 300–600 million years old.

As it orbits the Sun, Venus displays phases like those of the Moon in a telescopic view. The planet appears as a small and “full” disc when it is on the opposite side of the Sun (at superior conjunction). Venus shows a larger disc and “quarter phase” at its maximum elongations from the Sun, and appears its brightest in the night sky. The planet presents a much larger thin “crescent” in telescopic views as it passes along the near side between Earth and the Sun. Venus displays its largest size and “new phase” when it is between Earth and the Sun (at inferior conjunction). Its atmosphere is visible through telescopes by the halo of sunlight refracted around it.

The Venusian orbit is slightly inclined relative to Earth’s orbit; thus, when the planet passes between Earth and the Sun, it usually does not cross the face of the Sun. Transits of Venus occur when the planet’s inferior conjunction coincides with its presence in the plane of Earth’s orbit. Transits of Venus occur in cycles of 243 years with the current pattern of transits being pairs of transits separated by eight years, at intervals of about 105.5 years or 121.5 years—a pattern first discovered in 1639 by the English astronomer Jeremiah Horrocks.

In 1967, Venera 4 found Venus’s magnetic field to be much weaker than that of Earth. This magnetic field is induced by an interaction between the ionosphere and the solar wind, rather than by an internal dynamo as in the Earth’s core. Venus’s small induced magnetosphere provides negligible protection to the atmosphere against cosmic radiation.

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images: Mattias Malmer/NASA/JPL, Peter Barvoets,  Soviet Planetary Exploration Program, NSSDC, Marc Lecleire, ESA, C. Carreau,

ASTEROID DAY 2018

On 30 June 1908, 110 years ago, a 40 m asteroid struck the Earth over Tunguska, Siberia.

Destroying an area of forest the size of Greater London, this was the most significant impact event in Earth’s recent history.

Now recognised by the United Nations as Asteroid Day, 30 June marks a global opportunity to raise awareness of the threat and opportunity posed by the numerous rocky bodies traversing space.

Since 2009, ESA has played a leading role in the global hunt for risky asteroids and comets – known formally to astronomers as near-Earth objects (NEO) – and is currently developing cutting-edge widefield telescopes that will have the ability to scan the entire sky in just 48 hours.

ESA also carries out crucial analysis as part of its Space Situational Awareness (SSA) programme and mobilises observatories and astronomers worldwide through its SSA NEO Coordination Centre at the Agency’s ESRIN facility in Italy.

Each year, Asteroid Day is broadcast live across the globe with a packed programme that brings together astronauts, rock stars and scientists.

Highlighting our potentially vulnerable place in space, the live event also describes the many ingenious and yet not-far-from scifi potential solutions to these dangerous roaming rocks.

Each year hundreds of regional events also take place, with 78 countries so far having hosted concerts, community events, lectures and much more.

Apollo 11 Earthrise

Solar System Infographs

Our Amazing Solar System!

Could we create dark matter?

85% of the matter in our universe is a mystery. We don’t know what it’s made of, which is why we call it dark matter. But we know it’s out there because we can observe its gravitational attraction on galaxies and other celestial objects. 

We’ve yet to directly observe dark matter, but scientists theorize that we may actually be able to create it in the most powerful particle collider in the world. That’s the 27 kilometer-long Large Hadron Collider, or LHC, in Geneva, Switzerland.

So how would that work? In the LHC, two proton beams move in opposite directions and are accelerated to near the speed of light. At four collision points, the beams cross and protons smash into each other.

Protons are made of much smaller components called quarks and gluons. 

In most ordinary collisions, the two protons pass through each other without any significant outcome.

However, in about one in a million collisions, two components hit each other so violently, that most of the collision energy is set free producing thousands of new particles. 

It’s only in these collisions that very massive particles, like the theorized dark matter, can be produced.

So it takes quadrillions of collisions combined with theoretical models to even start to look for dark matter. That’s what the LHC is currently doing. By generating a mountain of data, scientists at CERN are hoping to find more tiny bumps in graphs that will provide evidence for yet unknown particles, like dark matter. Or maybe what they’ll find won’t be dark matter, but something else that would reshape our understanding of how the universe works entirely. 

And that’s part of the fun at this point. We have no idea what they’re going to find.

From the TED-Ed Lesson Could we create dark matter? - Rolf Landua

Animation by Lazy Chief