Observing the Universe
Why can't we see many of the stars and even our own Milky Way galaxy in the night sky?
Light pollution
What is length of a wave called?
Wavelength
What is the singularity?
A point of infinite density and temperature where space and time began.
Which stars live the longest?
Low mass stars
On the H-R Diagram, where you expect to find our Sun?
In the Main Sequence
What are the 3 ways astronomers can study the universe? For each one, explain why they would use it.
Naked eye: easy and everyone can use to see stars and the Moon
Visible light telescope: can enhance what our eyes can see from Earth
Advanced instruments: detect wavelengths of light our eyes can't see
What is the relationship between wavelength and frequency?
As wavelength increases, frequency decreases
What was formed during Big Bang Nucleosynthesis?
Hydrogen and helium.
Compare how low mass stars start and die to how very high mass stars start and die.
Low mass: start as nebula but die as white dwarf
Very high mass: start as nebula but die as black hole
How do the inner planets compare to the outer planets in composition and size?
Inner planets are smaller and rocky while the outer planets are bigger and gassy or icey.
Advanced instrument--Chandra X-Ray Space Telescope
1) Longest and shortest wavelength
2) Highest and lowest frequency
See board
Inside medium, high, and very high mass stars during nuclear fusion and supernova explosions.
Astronomers observe the Galaxy 041 that appears smooth and round with no visible arms. It contains mostly old, red stars and has very little gas or dust, meaning very little new star formation is occurring. What type of galaxy is this most likely?
Elliptical
Two new moons have been discovered around Saturn. Moon A is twice the far from Saturn as Moon B. How does the force of gravity of Moon A compare to Moon B?
Weaker than Moon B.
Astronomers detect the light from a distant star is shifted to longer wavelengths. What kind of instrument did they use? And, what can they learn about that star?
1) Visible light telescope and used spectroscopy.
2) Star is redshifting...so moving away
Why couldn't heavier elements form right after the Big Bang?
The universe cooled and expanded too quickly and there were no stars yet to do nuclear fusion.
Scientists study a new galaxy called the Mid-Size Magellanic Cloud that has no clear shape, lacks spiral arms, and appears distorted, possibly due to gravitational interactions with nearby galaxies. It contains both old and young stars scattered throughout. What type of galaxy is this most likely?
Which planet has the shortest orbit?
Which planet has the shortest day?
Mercury
Jupiter
Edwin Hubble collected and analyzed the data of many, many stars and their absorption spectra.
1) What type of instrument did the astronomers use to collect that star spectra?
2) What did Edwin Hubble notice about most of the stars in the universe?
3) What conclusion did Hubble then reach about the universe?
1) Visible light telescope with spectroscopy
2) Most stars were red shifting
3) Most stars were moving away from us so they universe must be expanding
What elements are most likely present within this star? See the board for the star spectra.
See the board.
What are 3 pieces of evidence that support the Big Bang Theory?
1) Redshift of most stars
2) Cosmic Microwave Background (CMB)
3) Abundance of light elements
A galaxy was once a spiral but has used up most of its gas and no longer forms stars. It still has a disk but no arms. What is it now?
Lenticular
Why are the inner planets made of heavy elements while the outer planets are gassy and/or icy light elements?
Heat near the Sun prevented gases from condensing and solar winds blew the light gases out towards the outer planets.