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What does China want to do on the Moon’s far side?

What does China want to do on the Moon's far side? 92

What will China’s Chang’e-4 mission learn about the far side of the Moon? Here are a few things the mission is designed to do.

Learn about the Moon’s history

No space mission has ever explored the far side from the surface. As such, it’s the first chance to explore a mysterious region of Earth’s natural satellite.

The “face” that’s never seen from Earth has some key differences to the more familiar “near side”. The far side has a thicker, older crust that is pocked with more craters. There are also very few of the “maria” (dark basaltic “seas” created by lava flows) that are evident on the near side.

Chang’e-4 has reportedly landed at a site known as Von Kármán crater, a 180km depression located in the far side’s southern hemisphere. But Von Kármán lies within a much bigger hole punched in the Moon – the South Pole-Aitken basin.

It’s the oldest, largest and deepest such basin on the Moon and formed when an asteroid – perhaps 500km across, or more – collided with it billions of years ago.

This event was so powerful that it is thought to have ploughed through the Moon’s outer crust layer and through into the zone known as the mantle.

One of the mission’s objectives is to study any exposed material from the mantle present at the landing site. This would provide insights into the internal structure and history of the Moon.

What does China want to do on the Moon's far side? 93
The South Pole-Aitken basin was formed by a giant impact billions of years ago

Indeed, data from orbiting spacecraft show that the composition of the basin is different from the surrounding lunar highlands. But exposed mantle material on the surface is just one possibility among several to explain this observation.

The rover will use its panoramic camera to identify interesting locations and its Visible and Near-Infrared Imaging Spectrometer (VNIS) to study minerals in the floor of the crater (as well as of ejecta – rocks thrown out by nearby space impacts).

Additionally, the Lunar Penetrating Radar (LPR) instrument will be able to look into the shallow subsurface of the Moon, down to a depth of about 100m. It could probe the thickness of the lunar regolith – the broken up rocks and dust that make up the surface – and shed light on the structure of the upper lunar crust.

After the huge impact that created the South Pole-Aitken basin, a large amount of melted rock would have filled the depression. The science team wants to use Chang’e-4 to identify and study variations in its composition.

Filling an astronomy gap

The far side of the Moon has long been regarded as an ideal spot for conducting a particular kind of radio astronomy – in the low-frequency band – because it’s shielded from the radio noise of Earth.

There’s a frequency band (below about 10MHz) where radio astronomy observations can’t be conducted from Earth, because of manmade radio interference and other, natural factors.

Chang’e-4’s lander is carrying an instrument called the Low Frequency Spectrometer (LFS) which can make low frequency radio observations. It will be used in concert with a similar experiment on the Queqiao orbiting satellite.

What does China want to do on the Moon's far side? 94
Radio telescopes on the Moon would be able to observe at frequencies not accessible to arrays on Earth

The objectives include making a map of the radio sky at low frequencies and studying the behaviour of the Sun.

Speaking in 2016, Liu Tongjie, from the Chinese space agency (CNSA), said: “Since the far side of the Moon is shielded from electromagnetic interference from the Earth, it’s an ideal place to research the space environment and solar bursts, and the probe can ‘listen’ to the deeper reaches of the cosmos.”

Thus, the mission will fill a gap in astronomical observation, allowing scientists to study cosmic phenomena in a way that has never been possible from our planet.

Radiation on the Moon

What does China want to do on the Moon's far side? 95
Understanding the radiation environment will be vital for future human exploration

Several space agencies want to land humans on the Moon in the not-too-distant future, and might send astronauts there for longer than we’ve ever stayed before. So understanding the potential risks from radiation are vital.

Earth’s thick atmosphere and strong magnetic field provide adequate shielding against galactic cosmic rays and energetic charged particles travelling from the Sun.

But astronauts on the Moon will be outside this protective bubble and exposed to particles travelling through open space at near the speed of light – with potentially damaging consequences for their health.

The Lunar Lander Neutrons and Dosimetry (LND) experiment, supplied by researchers in Germany, will aim to fill in some gaps in our understanding about the lunar radiation environment.

It will provide dosimetry (measure the ionising radiation dose that could be absorbed by the human body) with a view to future exploration, and contribute to understanding of particles originating from the Sun.

Source www.bbc.co.uk

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Space

KOI-5Ab, the curious planet that orbits in a system of three suns

KOI-5Ab, the curious planet that orbits in a system of three suns 98
Photo: (Caltech / R. Hurt (IPAC))

To us, the Sun alone seems perfectly normal, but our solar system is actually a strange exception.

Most stars in the Milky Way galaxy have at least one companion star. In a system 1,800 light-years away, astronomers have finally confirmed the existence of a gas giant planet orbiting stars in a triple star system.

Called KOI-5, the system is located in the constellation Cygnus, and the exoplanet was confirmed ten years after it was first detected by the Kepler space telescope.

In fact, the planet – now known as KOI-5Ab – was discovered by Kepler when it began operations back in 2009.

“KOI-5Ab was dropped because it was difficult and we had thousands of other candidates,” astronomer David Siardi of NASA’s Exoplanet Science Institute said.

“There were lighter dives than the KOI-5Ab, and every day we learned something new from Kepler, so the KOI-5 was almost forgotten.”

Exoplanet hunters tend to avoid the complexities of multi-star systems; of the more than 4,300 exoplanets confirmed to date, less than 10 percent are multi-star systems, although such systems dominate the galaxy. As a result, little is known about the properties of exoplanets in multi-star systems compared to those orbiting a lone star.

After Kepler’s discovery, Chardy and other astronomers used ground-based telescopes such as the Palomar Observatory, Keck Observatory, and the Gemini North Telescope to study the system. By 2014, they had identified two companion stars, KOI-5B and KOI-5C.

Scientists were able to establish that the planet KOI-5Ab, is a gas giant that is about half the mass of Saturn and 7 times the size of Earth, and is in a very close five-day orbit around KOI-5A. KOI-5A and KOI-5B, both of roughly the same mass as the Sun, form a relatively close binary system with an orbital period of about 30 years.

KOI-5Ab, the curious planet that orbits in a system of three suns 99

A third star, KOI-5C, orbits the binary system at a much greater distance, with a period of about 400 years – slightly longer than Pluto’s 248-year orbit.

“By studying this system in more detail, perhaps we can understand how planets are created in the universe.”

The discovery was announced at the 237th meeting of the American Astronomical Society.

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Space

Why the universe does not fit into science

Why the universe does not fit into science 100
Photo: YouTube

Science can be compared to an artist painting what he has never seen, or to a writer describing other people’s travels: objects that he has never seen, places where he has never been. Sometimes such scientific “arts” turn out to be beautiful and interesting, but most of them will forever remain only theories, because they are beyond human capabilities.

In fact, science has the right only to speculate: how our universe appeared, how old it is, how many stars and other objects it contains.

Universe model

Why the universe does not fit into science 101

How many stars are there in the sky?

With an unarmed eye, a person can see about nine thousand stars in the sky in one cloudless and moonless night. And armed with binoculars or a telescope, much more – up to several million. However, this is much less than their true number in the universe. Indeed, only in our one galaxy (the Milky Way) there are about 400 billion stars. The exact amount, of course, is not known to science. And the visible universe contains about 170 billion galaxies.

It is worth clarifying that scientists can see the universe 46 billion light years deep in all directions. And the visible (observable) universe includes the space accessible to our eyes from the moment of the Big Explosion. In other words, only this (accessible to human perception) space science refers to our universe. Science does not consider everything that follows.

It is believed that there are supposedly a ceptillion (10 to 24 degrees) stars in our universe. These are theoretical calculations based on the approximate size and age of the universe. The origin of the universe is explained by the Big Bang theory. This is why the universe is constantly expanding and the more time passes, the more complex the universe and its components become.

Why the universe does not fit into science 102

It is not entirely correct to consider and perceive this scientific theory “head-on”. Scientists always claim that that explosion was not exactly an explosion, and the point that exploded was not the only one. After all, it was everywhere, because space did not exist then. And in general – everything happened quite differently from what is described in the Big Bang theory, but all other descriptions of the origin of the universe are even more incredible and inaccurate.

Separate but interconnected

That which is beyond the reach of human perception is usually discarded by science, or recognized as non-existent. Recognizing one thing, science does not want to recognize the existence of the other, although everything in our world is interconnected and is not able to exist separately – by itself.

Each object of the universe is a part of it much more than an independent, separate object.

Any person, like any material object of our world, consists of components: organs, cells, molecules, atoms. And each of its constituent parts can represent the whole world. Separate, and at the same time connected with all the others.

However, science, as a rule, perceives all the components of the universe – people, animals, plants, objects, the Earth, the Sun, other planets and stars – as separate subjects, thereby limiting itself.

Why the universe does not fit into science 103

Even what is considered the visible universe, one of the atoms of which could be called our solar system, is not subject to the boundaries of human perception. But perhaps the atom is an exaggeration, and our solar system is not even an atom, but one of its elements!

How, being so far from the truth, can one reason about something with the degree of probability with which science tries to reason about the origin of the universe?

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Space

An unexplained wobble shifts the poles of Mars

An unexplained wobble shifts the poles of Mars 104

The red planet sways from side to side like a whirligig when it loses speed. The new study allowed scientists to notice that the poles of Mars deviate slightly from the axis of rotation of the planet. On average, they move 10 cm from the center with a period of 200 days.

Such changes are called the Chandler Oscillations  – after the American astronomer Seth Chandler, who discovered them in 1891. Previously, they were only seen on Earth. It is known that the displacement of the poles of rotation of our planet occurs with a period of 433 days, while the amplitude reaches 15 meters. There is no exact answer why this is happening. It is believed that the fluctuations are influenced by processes in the ocean and the Earth’s atmosphere.

Chandler’s wobbles on Mars are equally perplexing. The authors of the study discovered them by comparing data from 18 years of studying the planet. The information was obtained thanks to three spacecraft that orbit the Red Planet: Mars Odyssey, Mars Reconnaissance Orbiter and Mars Global Surveyor. 

Since Mars has no oceans, it is likely that the Red Planet’s wobbly rotation is due to changes in atmospheric pressure. This is the first explanation that researchers have shared. In the future, there should be new details about the fluctuations that have so interested the scientific community.

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