Footprints on the moon – Observation of the sky

Ken Tapping –
July 19, 2019 / 11h00 | story:
261456

Photo: spaceflightinsider.com

Fifty years ago, in July 1969, people from all over the world were glued to their television or radio, watching the progress of the first human expedition to another world: the Apollo 11 trip to the moon.

Two American astronauts have thus made the first human footprints on the lunar surface. It was perhaps the biggest event of this decade.

The 1960s were very exciting. It was the time of Woodstock, miniskirts, hippies, Flower Power, the Movement for Civil Rights, The Beatles and the Rolling Stones.

There was a rock band in every street and a nasty war in Vietnam. There was a widespread feeling that it was in the power of the younger generation to improve the world: the age of Aquarius.

It was a good time to realize a dream of centuries-old space travel.

The modern space period began on October 4, 1957, when the Soviet Union launched the first human-made object in orbit around the Earth.

The Sputnik 1 spacecraft could be seen as a star-shaped object moving in the sky among the stars and its sound signal can be heard by anyone with an ordinary shortwave radio.

The Soviet Union had scored a huge prestige point, and it was realized that big rockets could not only carry spacecraft; they can carry very large bombs. So began what has become the race to space.

In the following years, satellites were launched into orbit, space probes were sent to explore the solar system, and on August 12, 1961, the Soviet Union sent the first man into space, Yuri Gagarin.

Other countries, including the United Kingdom and China, have developed launchers and launched their own satellites. Canada has also entered the space age by developing satellites such as Alouette, launched with the help of American rockets.

In 1962, US President John Kennedy announced his intention to send astronauts to the moon before the end of the decade.

This required the development of new technologies, new techniques and a much larger launcher – the Saturn 5. The Mercury satellite and the two-man Gemini missions helped perfect spacecraft design and rendezvous techniques in orbit.

All this was necessary to put a man on the moon.

When we saw Neil Armstrong's blurry images and Aldrin's "Buzz" on television making their first footprints on the moon, many of us had the feeling of being on the doorstep. 39, a new age.

We could soon have a space station and make footprints on Mars before the 21st century.

As in most "New Ages", things took a little longer than expected. Cost was an element. We needed new technologies and a new approach. The exploration of the inhabited space should wait a little longer.

The International Space Station continues to be an important research site for the development of new space technologies, as well as for the identification and resolution of problems inherent to long-duration missions.

In the meantime, space exploration has continued, with the help of robotic astronauts. These allowed us to explore most of the solar system and to see other worlds closely.

What we saw surprised us. The recent overview of Pluto is an excellent example. In addition, the landers and rovers have made the surface of Mars almost as familiar as our own world.

Now, once again, we return to the Moon, to stay and head to Mars. It will not be a race to the space this time; it will be an international effort and Canada will be part of it.

The Outward Urge has been with us since our first outing from Africa, and it is not healthy to ignore. We can not stay locked in a world where the population is growing and competing for limited resources, like rats in a box.

We need a dream and new horizons.

• Shining Jupiter is in the south after dark
• Saturn is low in the southeast.
• The moon will reach the last quarter on the 24th.

Ken Tapping –
12 Jul 2019 / 11h00 | story:
260971

Photo: pics-about-space.com

The long stays of astronauts on the International Space Station have shown us that people can recover from long periods of weightlessness in free fall.

However, it would be better if these effects are avoided. When astronauts arrive home, they are often lifted from the probe.

It is very unlikely that when we arrive in a distant world after a long journey in space, friendly extraterrestrials are waiting to help us disembark.

Astronauts must experience gravity during the trip, or something of the sort.

Weightlessness is what we experience when we are in free fall, moving only by gravity. This applies not only when we come across something here on Earth, but also when we are in transfer orbit between the stopped and moving worlds, in response to the gravity of nearby bodies.

The obvious thing would be to avoid being in free fall. For example, if we kept the spacecraft engines running to add 9.8 meters per second to our speed, we would feel like on the surface of the Earth, with our usual weight.

We would run the engines for about halfway, stop them, return the ship and restart it. Our spacecraft was starting to slow down, slowing the ship 9.8 meters per second every second, so that when we arrived at our destination, we would go slowly enough to put ourselves into orbit or land.

Unfortunately, we still have only two types of space propulsion. We have engines that can produce huge thrusts for short periods, as needed, to get from the Earth's surface into orbit.

The other types are the plasma engines that produce tiny thrusts, which can operate more or less indefinitely because they consume their fuel very economically.

However, they are not able to give the push necessary to maintain the comfort of our astronauts. We need engines that produce moderate thrust that can be maintained for long periods of time.

Decades ago, science fiction writers came up with another approach, to spin the spaceship.

My family and I had a first-hand experience walking around an amusement park a few years ago. The carousel looked like a flying flying saucer mounted so that it could turn at high speed. Inside, almost vertical benches were attached to the outer wall of the "spaceship".

We were asked to lean against these benches. There was no window, so we could not feel the moment when we started to turn.

However, as the spin accelerated, we were increasingly pulled towards the wall, on the benches, until the direction of the ground was directed towards the wall, which had become the ground, and that the original soil was a vertical wall near our feet.

We can spin a real spacecraft in the same way, so that astronauts are pulled toward the outer wall, which gives them the impression of being exactly like gravity. There have been sci-fi stories of huge hollow cylinders with large spatial colonies living in farms, villages and towns attached to the inner wall.

The Arthur C. Clark book, Rendezvous with Rama, describes such a spaceship. An alternative is a big spinning wheel, like the 2001 space station, the Space Odyssey. In this case, the pbadengers will be inside the outside wall of the ring.

Another concept is a vehicle consisting of two spheres connected by a long tube. By turning this end to end, like a cheerleader's stick, the pbadengers of the spheres would suffer the same kind of pseudogravity.

The construction of rotating spaceships poses technical problems. One is the problem of stabilization. As people and other objects move on board, the center of gravity will move slightly and the rotation will flicker.

However, for the moment, rotating spacecraft seem to be the best option for flying to distant planets and being able to leave the ship.

• Jupiter dominates the southern sky during the night.
• Saturn rises around 22 hours.
• The moon will be full on the 16th and will reach the last quarter on the 24th.

Ken Tapping –
July 5, 2019 / 6:00 am | story:
260468

Photo: cosmos.esa.int

For two months, Jupiter is the most spectacular object of the sky after the sun and the moon.

The giant planet is located in the southeast after sunset and dominates the southern sky for most of the night. Look for a very bright, star-shaped, shiny object with a yellowish-white color.

Unlike the stars, the planets do not twinkle, so Jupiter shines regularly, in the manner of a plane landing lighthouse.

The planets revolve around the sun in almost circular concentric orbits.

Starting from the sun they are:

• Mercury
• Venus
• Earth,
• March
• Jupiter
• Saturn
• Uranus
• Neptune

Pluto was part of the ninth and the last planet.

In addition to having smaller orbits, the inner planets also move faster and thus take much less time to orbit the sun:

• Mercury 0.24 years,
• Venus 0.61 years,
• Earth one year
• March 1.9 years,
• Jupiter 11.9 years
• Saturn 29.4 years,
• Uranus 84.1 years
• Neptune 164.5 years old.

The result is that the inner planets regularly exceed those further away.

For Earth and Jupiter, it happened on June 10th. At that time, the Earth was exactly between Jupiter and the sun.

This meant that when the Earth was spinning, Jupiter was lying in the south, exactly 12 hours after sunset south.

That's why astronomers refer to the planet being "in opposition". The opposition is one of the best times to come out of the telescope and observe the planets in orbit outside the Earth.

They are closest to us and we have the longest time to see them without the sun in the sky.

When Galileo pointed his telescope at Jupiter for the first time in 1610, what he saw was revolutionizing his vision of the universe.

Today, we have much better telescopes and the best time to light them is Jupiter. Even if you only have a pair of binoculars, there will always be something to see, such as what excited Galileo.

You will see a beige colored disc crossed by darker lines or belts. Near the planet, you will see up to four star-shaped objects, all aligned, like beads on a wire. These are the four largest moons of Jupiter, coming out of the planet:

• io
• Europa
• Ganymede
• Callisto

As the nights go by, you will see them change position. They disappear behind the planet and pbad by, and you can sometimes see the shadow of one of the moons projected on the planet.

Galileo observed this, carefully noting how the positions of the moons changed over time and concluded that the moons gravitated around the planet.

As it was a time when it was taught that everything was around the Earth, the discovery of an exception was a corner opening the door to new ideas.

This has led to a growing realization that many things we observe in the sky become much easier to interpret if we badume that Earth and other planets gravitate around the sun.

If you have a telescope, you can take a closer look at the planet itself. This beige disc is not the body of the planet; it's just the peak of a very deep atmosphere.

Jupiter has a diameter more than 10 times greater than that of the Earth, but turns on itself in about 10 hours. While a point of the Earth 's equator is moving eastward at about 1670 km / h, a point of the Jupiter equator travels at around 45,000 km / h.

This furious rotation causes the clouds in the belt and causes gigantic and long-lasting storms.

On Earth, our time is spent in thin skin on the planet, a few kilometers thick. The rough, rocky ball that rotates underneath has a major effect on the formation and evolution of our weather conditions.

Jupiter is different. The planet is a gas giant and consists mainly of atmosphere. So we observe a weather machine without any soil underneath.

This raises a very interesting question. In the absence of ground anchor, why did the big red spot stay in the same place for hundreds of years?

This is something to think about when looking at this fascinating planet.

• Jupiter dominates the eastern sky after dark.
• Saturn rises around 22 hours.
• The moon will reach its first quarter on the 9th and will be full on the 16th.

Ken Tapping –
Jul 1, 2019 / 2:55 pm | story:
260152

Photo: Contribution

We often hear people say that "things float in space because there is no gravity".

This is not true.

Gravity extends to the whole universe and more locally, it keeps the moon in orbit around the Earth and the Earth and other planets orbiting the sun.

What is really happening?

A good way to start is to imagine an extremely enlarged version of the CN Tower.

The revolving restaurant and the observation terraces are 410 km from the ground. We chose this height because, as we eat, we can sometimes see the International Space Station speed up.

Since it is an imaginary tower, we can ignore the very obvious security issues. While enjoying your meal, you will also be able to admire the incredible panorama of the Earth and constantly changing cloudy landscapes, far below.

The only obvious difference will be that the restaurant and the observation galleries will be airtight and under pressure. The higher we rise above the ground, the lower the atmospheric pressure. Above about five kilometers, the air pressure is low enough that each breath does not provide enough oxygen, so we have trouble breathing.

At the top of our tower, there is hardly any air. One thing you may not notice, because it's so familiar, is that restaurant tables are laid out exactly as they are in restaurants closer to the ground.

• Knives
• forks
• plates
• wine glbades

None tend to float off tables and you can walk more or less normally. In fact, you weigh nearly 90% of your weight at sea level.

Imagine that you were wearing a spacesuit and that you were on the special outdoor observation deck. Do you want to go out and take a walk in the space?

If you did, you would fall to Earth with enough time to ask you what you did wrong. One thing you will notice is that you are now weightless.

This is what we live if we fall freely under gravity. We experience it for a short time, whether it's bungee jumping or one of the park's most exciting rides.

Astronauts traveling in space or doing acrobatics inside the International Space Station suffer from weightlessness because they also fall free under the action of gravity.

This condition is often described as a free fall. To clarify the situation, imagine that at the top of the tower is a very large gun, and a good supply of gunpowder and cannonballs.

Load the barrel and pull it out. As you can imagine, the cannonball follows a descending curved path under the gravitational pull until it hits the ground.

Charge it again, using more powder. The cannonball moves faster and follows a more progressive downward curve until it touches the ground further.

If you continue to shoot the cannon again and again, using more powder each time, the ball will hit the ground further and further.

However, you will come to a point where something strange is happening. As might be expected, the Earth's gravity pulls the ball into a curved trajectory down, but underneath, as the Earth is a sphere, the ground is curved underneath. The result is that the ball does not touch the ground, it keeps spinning around the Earth; it is in orbit.

To do this, the cannonball must leave the barrel of the gun at 27,600 km / h. This is the speed at which the International Space Station rushes past the windows of the restaurant, because like this cannonball, the station and its pbadengers fall freely around the Earth.

In practice, we choose not only to prevent our spaceship from hitting the ground, we must also keep them above the atmosphere, which will slow them down and make them fall.

Without a tower or cannon, putting something into orbit involves raising it above the atmosphere and then accelerating it horizontally so that it moves quickly enough to fall without losing the Earth.

Do not forget that astronauts who perform their acrobatics are just as subject to gravity as we are on the ground.

• Jupiter dominates the eastern sky after dark. Saturn rises around 22 hours.
• The moon will be new on Tuesday and will reach the first quarter on the 9th.