Categories: world

Canada got there first – Skywatching

Photo: sd.gsfc.nasa.gov In the 1 960s, Canada was the first country to successfully use a radio telescope thousands of kilometers in diameter. A technology was developed to make multiple radio telescopes, separated by thousands of kilometers, act as if they were joined. This technique, known as very long baseline interferometry or VLBI, was developed by a major cause: to find out which quasars really are. It was also very useful for something completely different: measuring the changing shape of the earth. The level of detail in an image is dictated by the size of the mirror or lens used to make it compared to the length of the waves Light waves are very short, so our eye lenses with a diameter of a few millimeters are good enough to see details so small as a percentage of the area on the moon disk. To record the same detail for waves that are centimeters or meters long, the lenses or mirrors must be huge. Our Synthetic Radio Telescope, which can provide radio images with details that can be achieved with our eyes, consists of a series of antennas 600 meters long. We can increase our eyes ability to discern fine details using a telescope or binoculars. This means that the students in our eyes become larger. But this is hard to do with radio telescopes. Modern engineering science and materials can give us rats up to 100 meters in diameter, but not larger. In the 1960s, a strange class of cosmic…

In the 1

960s, Canada was the first country to successfully use a radio telescope thousands of kilometers in diameter.

A technology was developed to make multiple radio telescopes, separated by thousands of kilometers, act as if they were joined.

This technique, known as very long baseline interferometry or VLBI, was developed by a major cause: to find out which quasars really are.

It was also very useful for something completely different: measuring the changing shape of the earth.

The level of detail in an image is dictated by the size of the mirror or lens used to make it compared to the length of the waves

Light waves are very short, so our eye lenses with a diameter of a few millimeters are good enough to see details so small as a percentage of the area on the moon disk.

To record the same detail for waves that are centimeters or meters long, the lenses or mirrors must be huge.

Our Synthetic Radio Telescope, which can provide radio images with details that can be achieved with our eyes, consists of a series of antennas 600 meters long.

We can increase our eyes ability to discern fine details using a telescope or binoculars. This means that the students in our eyes become larger. But this is hard to do with radio telescopes.

Modern engineering science and materials can give us rats up to 100 meters in diameter, but not larger.

In the 1960s, a strange class of cosmic radio sources called quasars was discovered. They were very small, looked like stars through our largest optical telescopes, and they are billions or billions of light-years away.

Most of their foreign properties were in the radio emissions they produced, so we wanted to make radio pictures of them. We now believe that they are driven by black holes.

Cosmic radio sources seem so small in the sky that most people are beyond the display’s ability to use radio telescopes, even the largest. This led to the development of techniques where we can combine groups of small radio telescopes into arrays larger than any possible antenna radio telescope.

Over time, most radio sources were imaged, but the quasars were unimaginable. We needed even bigger arrays. But the telescopes in a matrix must be interconnected, limiting these arrays to perhaps a few kilometers over.

Even the largest arrays were insufficient to handle quasars.

Something brand new was necessary. Can we make arrays without having to connect the antennas together? It was an international competition to achieve this. Canada came first.

The idea was to record on videotapes the signals received by different antennas. The bands from the different antennas would then be collected later for processing.

To make this possible extremely accurate, time signals were added to the bands. The antennas can now be anywhere on earth.

A matrix of earth’s size gave us some useful pictures. This is the technology that recently gave us our first ever photos of a black hole.

A very useful by-product of these VLBI experiments is a measurement of the positions of the antennas, including the distances between them, accurately to a few millimeters.

By setting antennas on different continents, we can measure how quickly the tectonic plates move and how the land masses extend, twist or otherwise change shape.

This works well because quasars small size, which makes them extremely difficult to form, also makes them ideal reference sources for measuring the positions of the antennas.

Our obsession with quasars has given us the ultimate ruler to measure our world.

  • Mars is very low and insignificant in the west and drops
  • Jupiter, which shines like a search light, rises around midnight
  • Saturn stands up at 2 am
  • The moon is full on the 18th. Ken Tapping –
    May 6, 2019 / 11:00 am | Story:
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    Until recently, one of the laughing jokes about fast radio outbreaks (FRB) is that the number of theories that tried to explain them was greater than the number of FRBs detected.

    The radio telescope CHIME (Canadian Hydrogen Intensity Mapping Experiment) changes it. This instrument has a huge field of view – much of the sky – and captures lots of them.

    We hope that this will lead us to get a better idea of ​​what they are. All we know at the moment is that the very short (milliseconds) outbreaks of radio emissions come from us or millions of light years away.

    The transmitted energy must be huge, so big, the only engines we know if it can drive them are neutron stars and black holes. We hope that the number of theories will soon begin to decline.

    Theories are the currency of science. Getting to a new theory is much more than having a free idea to explain something we see. The first step is to observe something and come up with a possible physical process or set of physical processes to explain it. It can be a relaxed idea.

    Science begins at the next step. It is about searching the literature for other work on the subject and then using this to erase the idea of ​​creating a coherent series of physical and mathematical arguments to account for what was observed. This is not the end of history.

    The new theory must make predictions. If it is correct, there will be other consequences we can look for in new observations. The theory must predict things that can be tested. Unless such a theory survives a long period of detailed examination and testing, it can finally be recognized as a “law” – one of the basic rules used by Mother Nature to drive the universe.

    Isaac Newton gave us good examples. He came up with a simple theory.

    If you double the object’s mass, it accelerates to half that speed.

    On the other hand, if you press twice the force, the object will accelerate twice as fast.

    The consequences of this simple idea are now recognized as Newton’s laws.

    He also theorized that objects attract each other with a force that is related to their masses and the distance between them. He came up with the idea of ​​gravity.

    Mathematically expressed Newton’s laws of motion and gravity have been tested and used over and over again, successfully and are now recognized as basic laws of nature.

    That’s why researchers are so unhappy with the concepts of dark matter and dark energy.

    When we saw that in most galaxies the stars moved in them too fast, we found the masses in the galaxies are much larger than we thought. However, we cannot see the missing mass.

    Someone suggested that the invisible mass consists of Dark Matter, an otherwise completely invisible “something” invented for our measurements to be meaningful.

    The expansion of the universe accelerates. This is not logical. If all the objects in the universe draw on all other objects, gravity should slow down the expansion.

    The only way that the expansion can accelerate is if any unknown outward force is at work.

    Enter the idea of ​​Dark Energy. As with Dark Matter, we have just given something a name, we have no explanations or analyzes to follow.

    This can change. The CHIME radio telescope is intended to map the hydrogen in the very young universe. This is when dark energy would be very active to start the first galaxies to form.

    This does not necessarily lead us directly to a theory, but it can at least tell us which way to go.

    • Mars lies low in the west after sunset.
    • Jupiter rises around midnight
    • Saturn rises at 2 am
    • Moon will reach the first quarter of the 11th
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