Astronomy

How does natural selection work?

Within the wide variety of every species, those organisms with advantageous characteristics are more likely to survive and breed, so these characteristics are kept and passed on down the generations.

example of pseudoscience

astrology and horoscopes

What characteristics does a good scientific model (or theory) have?

based on reliable observations. able to explain the characteristics of the observations used to formulate it. predictive. able to explain phenomena that were not used to develop the model. able to be refined when new, credible, conflicting observations arise. limited and simplifies a concept, theory, or object. physical (2-dimensional or 3-dimensional) or mathematical (includes a single formula or many formulae) or conceptual (digital or print). a computer or physical simulation of a natural phenomenon.

What are Kepler's three laws of planetary motion?

1. The orbit of each planet is an ellipse with the Sun at one focus. 2. As a planet moves around its orbit it sweeps out equal areas in equal times. 3. More distant planets orbit the Sun at slower average speeds: p2 = a3.

Why is the sky blue? Why are sunsets red or orange?

A clear cloudless day-time sky is blue because molecules in the air scatter blue light from the sun more than they scatter red light. When we look towards the sun at sunset, we see red and orange colours because the blue light has been scattered out and away from the line of sight.

What is confirmation bias? Give an example.

A confirmation bias is a type of cognitive bias that involves favoring information that confirms your previously existing beliefs or biases. 1 For example, imagine that a person holds a belief that left-handed people are more creative than right-handed people.

What methods have astronomers used to detect planets around stars other than the sun?

A handful of ingenious methods have been used to detect the planets too far away for us to see Transit. Imagine looking at a small planet orbiting a star far, far away. Radial Velocity Direct Imaging Gravitational lensing.

How is a scientific hypothesis different to how a hypothesis is described to schoolchildren?

A scientific hypothesis is the initial building block in the scientific method. Many describe it as an "educated guess," based on prior knowledge and observation.

How is a scientific theory different from the popular use of the word theory?

A scientific theory is a well-substantiated explanation of some aspect of the natural world, based on a body of facts that have been repeatedly confirmed through observation and experiment. Such fact-supported theories are not "guesses" but reliable accounts of the real world.

What is the difference between a solar day and a sidereal day?

A solar day is the time it takes for the Earth to rotate about its axis so that the Sun appears in the same position in the sky. The sidereal day is ~4 minutes shorter than the solar day. The sidereal day is the time it takes for the Earth to complete one rotation about its axis with respect to the 'fixed' stars.

What causes lunar and solar eclipses?

A solar eclipse happens when the New Moon moves between Earth and the Sun while a lunar eclipse occurs when Earth casts a shadow on the Full Moon. If a planet comes between Earth and the Sun, and is visible as a black dot against the Sun, it is called a planet transit.

How do scientists know that astrology doesn't work?

Although astrology can seem like a science because it tries to explain something from the natural world, astrology doesn't have a verifiable mechanism, and astrologers don't have a critical approach towards their claims. ... Therefore, astrology cannot be considered a science.

What is the difference between astronomy and astrology?

Astronomy is the study of the universe and its contents outside of Earth's atmosphere. Astronomers examine the positions, motions, and properties of celestial objects. Astrology attempts to study how those positions, motions, and properties affect people and events on Earth.

Where in the sky is the sun at noon?

At the equator, the noon sun is straight overhead on the equinoxes. And after you pass 23.5° south latitude (the Tropic of Capricorn), the noon sun is always in the north. Much farther south is the Antarctic Circle, where the sun never quite rises on the June solstice and never quite sets on the December solstice.

How has life on earth changed the earth's atmosphere?

Before life began on the planet, Earth's atmosphere was largely made up of nitrogen and carbon dioxide gases. After photosynthesizing organisms multiplied on Earth's surface and in the oceans, much of the carbon dioxide was replaced with oxygen.

How is science different from pseudoscience?

Both pseudoscience and science purport to exalt evidence, yet only science reliably, repeatedly, and rigorously tests hypotheses to discover evidence which either supports or denies the hypothesis. Pseudoscience looks only for evidence that supports the hypothesis.

What building blocks of life were found on meteorites from space?

Building Blocks of DNA Found in Meteorites from Space. Meteorites contain a large variety of nucleobases, an essential building block of DNA. The components of DNA have now been confirmed to exist in extraterrestrial meteorites, researchers announced.

What methods have people used to try to communicate with extraterrestrial civilizations?

Communication with extraterrestrial intelligence or CETI is a branch of the search for extraterrestrial intelligence that focuses on composing and deciphering interstellar messages that theoretically, could be understood by another technological civilization.

How do the planets appear to move in the sky in the course of a day? Over months or years?

During a night (or day) the planets appear to move across the sky along with the stars, due to the rotation of the Earth. But from night to night the planets slowly move relative to the stars. Usually, they move west to east relative to the stars.

Can electromagnetic radiation travel through a vacuum? How can you tell?

Electromagnetic waves are waves which can travel through the vacuum of outer space. Mechanical waves, unlike electromagnetic waves, require the presence of a material medium in order to transport their energy from one location to another.

Give an example of a scientific theory that is also a fact.

For example, no new evidence will demonstrate that the Earth does not orbit around the sun (heliocentric theory), or that living things are not made of cells (cell theory), that matter is not composed of atoms, or that the surface of the Earth is not divided into solid plates that have moved over geological timescales

Which kind(s) can get through the earth's atmosphere?

Fortunately for life on Earth, our atmosphere blocks out harmful high-energy radiation like x-rays, gamma rays and most of the ultraviolet rays. The atmosphere also absorbs most of the infrared radiation which reaches the Earth from space.

What was new and interesting about Galileo's telescopic observations?

Galileo's Observations of the Moon, Jupiter, Venus and the Sun. When Galileo pointed his telescope at Jupiter, the largest planet in our solar system, he made a startling discovery. The planet had four "stars" surrounding it. Within days, Galileo figured out that these "stars" were actually moons in orbit of Jupiter.

Which kinds carry the most energy?

Gamma Ray The different types of EM radiation correspond to different amounts of energy per photon. Gamma ray and X-ray photons have the most energy, radio frequency photons have the least energy, while ultraviolet, infrared, and visible light photons have intermediate energies.

How do those elements compare to the most abundant elements in the universe?

Hydrogen is the most abundant element in the Universe; helium is second. However, after this, the rank of abundance does not continue to correspond to the atomic number; oxygen has abundance rank 3, but atomic number 8. All others are substantially less common.

What can be done to improve the resolving power of radio telescopes?

Increasing Resolution In A Radio Telescope Since the resolving power of a telescope is inversely proportional to the wavelengths of radiation it receives, the only way to increase the resolving power of a radio telescope is to increase the diameter of its dish.

What causes retrograde motion?

It happens for a few months at different times of the year when we go between some outer planets and the sun. It is not real motion, it is an illusion of motion that happens because our motion on Earth is faster.

What are the most abundant chemical elements in life on earth?

Living organisms often contain trace amounts of several elements, but the most abundant ones are oxygen, carbon, hydrogen, nitrogen, calcium and phosphorus. Oxygen. Oxygen is the most abundant element contained within living organisms, composing about 65% of the human body. Carbon. Hydrogen. Nitrogen. Sulfur. Phosphorus.

What determines the magnification of a telescope? Can you compute the magnification of a telescope?

Magnification (power): The amount that a telescope enlarges its subject. It's equal to the telescope's focal length divided by the eyepiece's focal length. As a rule of thumb, a telescope's maximum useful magnification is 50 times its aperture in inches (or twice its aperture in millimeters).

How are the three types of spectra produced?

Most light sources can be classified into three main types: continuous, absorption, and emission. A hot, opaque object, like the filament in an incandescent light bulb, emits a continuous spectrum, having light of all wavelengths. A hot, dense gas is another example of an object that emits a continuous spectrum.

What are causes of mutations?

Mutations can also be caused by exposure to specific chemicals or radiation. These agents cause the DNA to break down. So the cell would end up with DNA slightly different than the original DNA and hence, a mutation.

What are Newton's three laws of motion? Why are they so useful?

Newton's law are very important because they tie into almost everything we see in everyday life. Newton's laws speak very generally all forces, but to use them for any specific problem, you have to actually know all the forces involved, like gravity, friction, and tension.

Is there gravity in space? How can you tell?

No. Astronauts float around in space because there is no gravity in space. Everyone knows that the farther you get from Earth, the less the gravitational force is. Well, astronauts are so far from the Earth that gravity is so small. This is why NASA calls it micro gravity.

In what ways have astronomical events affected life on earth?

On a more pressing level, astronomy helps us study how to prolong the survival of our species. For example, it is critical to study the Sun's influence on Earth's climate and how it will affect weather, water levels etc. Astronomy is one of the few scientific fields that interacts directly with society.

What building blocks of life were easily created in laboratory experiments?

Organic compounds had been formed, most notably some of the "building blocks of life," amino acids. Amino acids are necessary to form proteins which themselves form the structure of cells and play important roles in the biochemical reactions life requires.

How do refracting telescopes work? reflecting telescopes?

Refracting telescopes use lenses to focus the light, and reflecting telescopes use mirrors. Refracting telescopes work by using two lenses to focus the light and make it look like the object is closer to you than it really is. Both lenses are in a shape that's called 'convex'.

How do scientists distinguish correct ideas from incorrect ideas?

Scientific testing involves figuring out what we would expect to observe if an idea were correct and comparing that expectation to what we actually observe. Scientific ideas are judged democratically based on popularity. ... Scientists are judged on the basis of how many correct hypotheses they propose ... If you are interested in learning about the difference between induction and deduction, likely to be wrong as it does from figuring out which are supported by the evidence.

What is the brightest star in the sky?

Sirius

What was Ptolemy's model of the solar system like? Copernicus's?

The Copernican model displaced the geocentric model of Ptolemy that had prevailed for centuries, which had placed Earth at the center of the Universe. Retrograde motion of the planets is explained by the Earth's motion. The distance from the Earth to the Sun is small compared to the distance from the Sun to the stars.

What and when are the equinoxes/solstices?

The December solstice marks the start of winter: at this point the South Pole is tilted closest to the Sun, and the Sun's rays are directly overhead at the Tropic of Capricorn. (In the Southern Hemisphere the seasons are reversed.) The equinoxes happen in March (about March 21) and September (about September 23).

How does the sun appear to move in the sky in the course of a day? In the course of a year?

The Earth spins on its axis, it looks like the Sun is moving across the sky. So because the Earth is facing the Sun at a different angle each day, the "path" the Sun makes in the sky will be different each day of the year.

Why does the moon appear to go through different phases?

The Moon appears to go through phases. The reason that we do not always see a Moon which is half lit is because of our position relative to the Moon and the Sun. As the Moon moves in its orbit, different portions of it appear (to us!) to be lit up as we look at it from Earth. This is why we see lunar phases.

What did the ancient Greeks contribute to the study of astronomy?

The ancient Greeks were some of the first people to study the sky and understand astronomy. They realized the Earth was a sphere and tried to measure its size. They also created an idea of a geocentric solar system that, while incorrect, helped us understand the universe for hundreds of years.

How does the moon appear to move in the sky in the course of a day? In the course of a month?

The answer is that the moon is moving. So the moon's motion has two parts to it. It looks like it's moving around the earth once per day along with everything else, but in addition to that it is actually moving around the earth once per month. That is what makes it move to a different place on the sky.

Is the ultraviolet radiation from the sun good or bad for life on earth? Why?

The atmosphere does little to shield these rays—most UVA radiation reaches Earth's surface. UVA rays cause skin aging and eye damage, and can lower your body's ability to fight off illness. UVA rays also contribute to the risk of skin cancer.

What is the brightest star in the night sky? How can you find that star?

The brightest star in the sky is Sirius, also known as the "Dog Star" or, more officially, Alpha Canis Majoris, for its position in the constellation Canis Major. Sirius is a binary star dominated by a luminous main sequence star, Sirius A, with an apparent magnitude of -1.46. It can be also seen with a naked eye.

If we wanted to communicate with an extraterrestrial civilization, what would be a good method?

The cultural impact of extraterrestrial contact is the corpus of changes to terrestrial science, ... To detect extraterrestrial civilizations with radio telescopes, one must identify an ... to refocus projects for communication with extraterrestrial intelligence. ..... quickly our differences worldwide would vanish if we were facing an alien

What are the different types of electromagnetic radiation? Which kind(s) can we detect with our eyes?

The different types of electromagnetic radiation shown in the electromagnetic spectrum consists of radio waves, microwaves, infrared waves, visible light, ultraviolet radiation, X-rays, and gamma rays. The part of the electromagnetic spectrum that we are able to see is the visible light spectrum. or in other words "visible" or "optical".

How long has it been known that the earth is (approximately) round? How could people back then tell that it's round?

The earliest documented mention of the spherical Earth concept dates from around the 5th century BC, when it was mentioned by ancient Greek philosophers. Using the knowledge that the Sun is very far away, the ancient Greek geographer Eratosthenes performed an experiment using the differences in the observed angle of the Sun from two different locations to calculate the circumference of the Earth.

What took longer: for life to appear on earth or for life to become complex (e.g., multicellular)?

The first known single-celled organisms appeared on Earth about 3.5 billion years ago, roughly a billion years after Earth formed. More complex forms of life took longer to evolve, with the first multicellular animals not appearing until about 600 million years ago.

Why did astronomers want to have a telescope in space?

The main reason we put telescopes into space is to get around the Earth's atmosphere so that we can get a clearer view of the planets, stars, and galaxies that we are studying. Our atmosphere acts like a protective blanket letting only some light through while blocking others. Most of the time this is a good thing.

What makes carbon a good element for life to be based on?

The most important characteristics of carbon as a basis for the chemistry of life are that each carbon atom is capable of forming up to four valence bonds with other atoms simultaneously, and that the energy required to make or break a bond with a carbon atom is at an appropriate level for building large and complex

Why do scientists not take astrology seriously?

The reason most scientists don't believe in astrology is because it is not consistent with our theories that have been tested by experiment.

What factors affect whether there are a lot of other civilizations in our galaxy?

The remarkable and subtle effect of this is that, depending on how many factors you think appropriate, you can get the conclusions you want while appearing reasonable and conservative throughout. That is, if you think many civilizations exist, you can use the Drake equation to demonstrate this. If you think we are the only ones, you can get the equation to say that as well. With this in mind, we should approach the Drake equation as a way of framing our discussion as opposed to as a method of determining the answer rigorously. The equation itself and its factors The original form of the equation was written by Frank Drake in 1960 in preparation for a meeting in Green Bank, West Virginia. It says: N = R ∗ × fp × ne × fl × fi × fc × L .

What determines the resolving power of a telescope? Can you compare the resolving power of two telescopes?

The resolving power is measured in the absolute smallest angle that can be resolved. The absolute minimum resolvable angle (smallest visible detail) in arc seconds = 252,000 × (observation wavelength) / (objective diameter).

How are spectra used to determine what stars are made of?

The spectra of the Sun and stars exhibited bright and dark lines called Fraunhofer lines. These were shown to be caused by elements emitting or absorbing light at specific wavelengths. Because each element emits or absorbs light only at specific wavelengths, the chemical composition of stars can be determined.

Which kind of spectrum does starlight usually produce? Why? Is that true for the sun too?

The spectrum of a star is composed mainly of thermal radiation that produces a continuous spectrum. The star emits light over the entire electromagnetic spectrum, from the gamma rays to radio waves. The Sun emits radiation right across the electromagnetic spectrum, from extremely high-energy X-rays to ultra-long-wavelength radio waves, and everything in-between. The peak of this emission occurs in the visible portion of the spectrum.

How does the gravitational force between two objects change if you change the mass of one of the objects or the distance between the two objects?

The strength of the gravitational force between two objects depends on two factors, mass and distance. the force of gravity the masses exert on each other. If one of the masses is doubled, the force of gravity between the objects is doubled. increases, the force of gravity decreases.

For what reasons might people eventually colonize space?

The two most common in favor of colonization are survival of human civilization and the biosphere in the event of a planetary-scale disaster (natural or man-made), and the availability of additional resources in space that could enable expansion of human society.

What causes tides?

Tides are periodic rises and falls of large bodies of water. Tides are caused by the gravitational interaction between the Earth and the Moon. The gravitational attraction of the moon causes the oceans to bulge out in the direction of the moon.

What determines the light-gathering power of a telescope? Can you compare the light-gathering power of two telescopes?

To compare light-gathering powers of two telescopes, you divide the area of one telescope by the area of the other telescope. For example: a 40-centimeter mirror has four times the light-gathering power as a 20-centimeter mirror: [( 402/4) / ( 202/4) = (40/20)2 = 4].

During a solar eclipse, are the rays that the sun emits more harmful to your eyes than the rays that the sun emits at other times? Explain.

Total solar eclipses produce harmful rays that can cause blindness. During a total solar eclipse when the disk of the moon fully covers the sun, the brilliant corona emits only electromagnetic radiation, though sometimes with a greenish hue. Looking at the sun during an eclipse is more dangerous than looking at full sun. The darkness that accompanies an eclipse can override the natural tendency to squint and avert the eyes, increasing the amount of ultraviolet radiation landing on the retina and making it more likely that you'll sustain eye damage.