Science Chapter 16
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An area of the sky and all the stars visible in that area.
Any one of the 88 areas in the sky that are used to identify and name the stars
the passage of the Moon through Earth's shadow
the passage of the Moon between the Sun and Earth
a giant ball of hot, glowing gases
How do you know the Earth is moving?
- the Sun and starts appear to move across the sky
- the seasons change
How long does it take Earth to make a rotation?
23 hours and 56 mins or rounded to 24 hours
Which direction does Earth turn when it rotates?
From west to east; because of this rotation everything else appears to move east to west
What causes day to turn into night?
the Earth's rotation
How long does it take for Earth to make one revolution?
About one year or 365 days
How long does it take the Moon to make a full revolution around the Earth?
How many stars do scientists estimate there are?
1 billion trillion. That is a 1 with 21 zeros behind it.
What star is nearest to Earth and the most important to Earth?
Why can't you see the stars during the day?
Because the sun is so bright.
How many constellations is the sky divided into?
Earth spins around its _________.
Earth completes one ____________ each day.
A(n) ___________is part of the sky used to identify stars.
During a(n)________, the Moon casts its shadow on Earth.
During a(n)________, the Moon passes through Earth's shadow.
Earth takes a year to complete one _________ around the Sun.
The constellations seen in the Northern Hemisphere that never appear to rise or completely set are
Explain what causes seasonal changes
- Earth revolves around the Sun. Sun’s path in the sky changes
- Earth’s axis is tilted. Sunlight is more direct or less direct.
- Hours of sunlight vary.
- Temperatures vary.
The Sun rises in the east and sets in the west because
Earth rotates from west to east
What is a supernova?
a gigantic explosion of a star millions of billions of times brighter than the star was
What is a black hole?
a point in space with a force of gravity so strong that nothing within a certain distance can escape being sucked in
a hugh system of stars, dust, and gas held together by gravity.
the distance light travels in one year
a could of gas and dust in which new stars form
Seasons, phases of the Moon, and the rising and setting of the Sun are _________ that are seen in the sky.
An equinox is the time of the year when day and night are of _________ length.
A(n)___________is a star map drawn on metal plate.
A sextant measures the angle between the ________ and a point in the sky.
Isacc Newton developed a __________ telescope that showed objects in sharper detail.
Telescopes collect and concentrate _________.
Radio telescopes have__________ that collect and focus radio waves.
What were some of Galileo's discoveries in astronomy?
He discovered that the Moon has mountains and that Sun spins. He discovered that Jupiter has four moons that orbit around it. He also discovered that Earth is not the center of the universe and that Earth and the other planets revolve around the Sun.
True / False
The hottest stars are red stars?
What are the three layers of the Sun?
Photospere, chromosphere, and the corona.
What is a white dwarf star?
One that has no fuel to make its own energy.
What is a spiral galaxy?
A galaxy that has a bright, bulging middle and wispy arms fanning out from the center.
The half of Earth north of the equator is called the _________ Hemisphere.
The Sun seems to travel across the sky because __________ is spinning.
____________ change with the seasons because Earth is traveling around the Sun.
What constellation can you only see in the Southern Hemisphere?
The constellation Centaurus.
What galaxy is earth part of?
The Milky Way.
Why can you only see some constellations during some season and not others?
Because the Earth is traveling around the Sun. Earth is moving.
How did people long ago develope calendars?
By using the predicatble cycles in the sky. They watched the patterns (repeated events) such as the seasons, the phases of the Moon, and the rising and setting of hte Sun each day.
What did ancient cultures thinks about eclipses?
They thought they meant that something bad was going to happen.
Why did scientists think that the people who built Stonehedge had a good understanding of the sun and the seasons?
Because Scientists agreed that the stone circles were linked to astronomy. Some stones pointed to the position in the sky where the Sun rises and sets on the longest day of the year. Other stones marked the rising of the Sun or the Moon at different times during the year.
How did Issac Newton's telescope improve upon earlier telescopes?
Newton developed the reflecting telescope. Earlier telescopes used lenses to focus light and magnify distant objects while Newton's used a curved mirror. It allowed people to see objects that were dimmer and farther away and to see the objects in sharper detail.
How are the Keck telescopes different from radio telescopes?
Keck telescopes have mirrors that work together as a system to gather visible light and infared radiation. They are used to study very distant stars. Radio telescopes look like a satellite dish. They don't have mirrors or lenses. The bowl-shaped dish collects and focuses radio waves given off by distant objects.
Why do telescopes in space get a more complete picture of space objects?
Conditions are perfect. It is always clear and dark and electromagnetic radiation is not blocked.
What kind of energy does the Sun give off?
Thermal energy and light energy.
What are the Sun's two main components?
Hydrogen and helium gas.
What do the different colors of stars represent?
- Red= coolest
- Orange and yellow= somewhat hotter
- White or blue-white= the hottest stars
What makes stars bright?
The amount of energy they give off.
What are sunspots?
Sunspots are dark spots that are seen moving along the face of the Sun and prove the Sun must be rotating. They are part of the photosphere. They look dark because they are not as hot as the rest of the photosphere. The number of sunspots changes in cycles of about 11 years. Sometimes there are a lot and sometimes there are only a few.
What do we know about the Sun's rotation?
The Sun rotates more slowly at its poles than at its equator.
Describe the life of a star.
- Nebula- the forming of new stars from a cloud of gas and dust.
- White dwarf- star has used up all its energy and is dying. The core of the star shrinks down to a white dwarf star. Star cools down and then becomes known as a black dwarf.
- Supernova- massive star that has shrunk until it can shrink no more and then explodes and leaves behind a ball of neutrons which are called a neutron star.
- Black hole- If the core was massive (more than three suns) the core's own gravity will keep causing it to shink on itself until it becomes a black hole. It pulls everything into it with in a certain distance.
What is the greatest type of galaxy that has been discovered?
Different types of galaxies.
- Spiral- pinwheels; bright and bulging middles and wispy arms that fan out from the center.
- Elliptical- almost round or more oval like a football. These are the largest galaxies we know but also have smaller galaxies than our galaxy.
- Irregular- galaxies that have no real shape. These are probably young galaxies in which stars are still forming.
What type of galaxy is the Milky Way?
What constellation can be seen in the Northern Hemisphere but not the Southern Hemisphere?
How the Milky Way and the constellation Centaurus are similar? How are they different?
The Milky Way and the constellation Centaurus are similar in there shape. The Milky Way is a spiral galaxy that has wispy arms that fan out from the bulging bright center. The Centaurus constellation is an arm of the Milky Way galaxy. This constellation appears to have arms and legs and has a bright star in the center.
They are different in that Centaurus is a constellation of stars in the Milky Way and it a small portion of the Milky Way. The Milky way is a large galaxy that is a hugh system of stars, dust, and gases held together by gravity.
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