Astronmy HW 1
docx
keyboard_arrow_up
School
Sam Houston State University *
*We aren’t endorsed by this school
Course
1404
Subject
Astronomy
Date
Jan 9, 2024
Type
docx
Pages
3
Uploaded by PrivateUniversePony25
Homework 1 question 1
1a. Light from the closest star to the Sun, Proxima Centauri, takes 4.24 years to reach Earth. Calculate
the distance to Proxima Centauri. Write your answer longhand (not in scientific notation) and then show
how to put your answer into scientific notation
One light year is 6.32x10^4 x 4.24
267968 is the distance
Scientific Notation: 2.68x10^5 Au
1b.
As Earth revolves around the Sun every 12 months, we view the night sky from a slightly different
point of view than we had 6 months earlier. For the closest stars to the Sun, we can measure a very small
shift in nearby stars' positions compared to more distant stars in the background. This phenomenon,
which we'll revisit later in the semester, is called
parallax.
The farther away a star is, the smaller the shift
is.
P= 57.3 / d
P=57.3 / 2.68x10^5
P= 0.000213831502
Scientific Notation: 2138x10^-4
1c. Because Proxima Centauri is the closest star to the Sun, it will show the largest parallax of any star in
the sky (other than the Sun). The human eye can see angles as small as approximately 0.0167°, where
the ° symbol means degrees. Calculate how many times larger this angle is compared to Proxima
Centauri's parallax.
57.3 / 0.000213831502 = 267,968
The parallax is 267968 x greater AC’s more.
1d. Having established that stars show no visible parallax and must be much farther away than anything
in the Solar System is, let's turn our attention to the Sun and the Moon.
Suppose you observe that you can see exactly half of the illuminated side of the Moon, implying that the
Sun is at a 90° angle from Earth as seen from the Moon. (See the figure below.) Suppose you measure
the angle between the Sun and the Moon to be 89.8°.
This means that of the three angles in the Earth-Moon-Sun triangle, you know the values of two of the
angles. Given that the three angles in every triangle add up to 180°, what is the value of the third angle in
this scenario? Your answer should have units of degrees.
180-90-89.8=0.2 degrees
1e. Calculate the distance from Earth to the Moon. Write your answer longhand and then show how to put
your answer into scientific notation.
M= 1.75x10^-2 x sun’s angle
M= 1.75x10^-2 x 0.2 degrees = 0.0035 Au
(3.5x10^-3) Au
1f.
How would this underestimate of the angle between the Sun and the Moon affect our calculation of the
distance from Earth to the Moon? Would we have calculated a smaller distance to the Moon, the same
distance, or a larger distance? Use the equation from part 1E to explain your answer.
It would have resulted in a Gogus, large numbers overestimations for the moon’s distance.
If 180-90-87=3, then 1.75x10^-2 x 1 x 3 = 0.0525 Au
Homework 1 question 2
2a.You observe that at a particular time of day on a particular day of the year, the Sun is directly overhead
in Syene, a city in Egypt (which was part of ancient Greece). But at the same time in Alexandria, another
Egyptian city almost due north, the Sun is 7.14° away from being directly overhead. What fraction of a full
360° circle is this angle?
7.14 / 360 = 119 degrees / 6000 = 0.01983
2b. What is the circumference of Earth? Write your answer longhand (not in scientific notation) and then
show how to put your answer into scientific notation.
493 miles / 0.019833 = 24857.1486 miles
Scientific Notation: 2.49x10^4
2c. Suppose you take a vacation from Egypt to Quito, a city in Ecuador very close to Earth's Equator.
Compared to someone standing at Earth's North Pole, who spins in place due to Earth's daily rotation,
how fast are you traveling through space simply by being on Earth at the Equator? Write your answer
longhand and then show how to put your answer into scientific notation.
2.4857.1486 / 24 = 1035.714286 mph
Scientific Notation: 1.036x10^3 mph
2d. What is Earth's diameter in miles? Write your answer longhand and then show how to put your
answer into scientific notation.
The Earth’s diameter in miles is D= c / 3.14
D= 24857.14286 / 3.14 = 7916.287534 miles
Scientific Notation: 7.91629x10^3 miles
2e. What is Earth's volume? Use scientific notation.
V= 0.524xD^3
0.524 x 7916.2875^3 = 259953675000 miles^3
Scientific Notation: 2.59953675x10^11 miles^3
2f. The volume of the Sun is 3.38 x 10
17
mi
3
.
How many Earths would fit inside the Sun?
Sol / Terma V = 1300231.666 earth’s per sol.
Homework 1 question 3
3a. Why was Pluto reclassified? Is Pluto any different now than it was before?
Pluto was reclassified as a dwarf planet by the (IAU) in 2006 because it did not meet the three
criteria the IAU uses to define a full-sized planet. It doesn't share common characteristics with
other planets, that is its size, mass, and the shape of its orbit.
3b. Mike Brown makes the statement in this article that "Science is self-correcting eventually, even when
strong emotions are involved." What does he mean by this? How does it relate to what you learned about
the nature of science in Section 1.2?
Science is not a belief system but a process of skepticism and testing.
3c. Is the reclassification of Pluto a unique event?
No
Have similar "self-corrections" happened before?
Yes
Are these self-corrections a weakness or a strength of sci-ence? (Consider Section 1.2.)
No. It shows
that science can reevaluate old ideas when new evidence is discovered.
3d. What if Pluto had not been reclassified?
If Pluto had not been reclassified, we would still see it as
the ninth and smallest planet in our solar system, but we would also have to accept that there are
many other similar objects beyond Pluto that could also be considered planets.
How would we classify Ceres, Charon, and the many other Pluto-like objects?
Dwarf Planets
How many planets would there be in the Solar System if we included all the ones that are Pluto-like?
Pluto is one of the four known dwarf planets in the solar system, along with Ceres, Makemake and
Eris. These objects are much smaller than the eight major planets and have not cleared their
orbital neighborhood of other icy bodies
. If we included all the dwarf planets as planets, there
would be 12 planets in the solar system.
3e. How does this article fit into the scheme of the scientific method that you learned about in Section
1.2?
The article “Pluto demoted to Dwarf Planet” fits into the scheme of the scientific method that
I learned about in Section 1.2 as follows:
●
The observation was that there were other objects in the Kuiper belt that were similar or
larger than Pluto.
●
The hypothesis was that Pluto was not unique or special enough to be considered a planet
among these objects.
●
The experiment was to define what a planet is and apply it to Pluto and other objects.
●
The result was that Pluto did not meet the criteria for being a planet and was reclassified
as a dwarf planet.
Explain how the reclassification of Pluto is an example of the scientific method at work.
●
Observation: Scientists discovered many objects beyond Pluto that were similar in size
and composition to Pluto, such as Eris, Makemake, and Haumea.
●
Question: Is Pluto a unique planet or one of many similar objects in the outer solar
system?
●
Hypothesis: Pluto is not a planet, but a dwarf planet, a new category of objects that share
some characteristics with planets but do not meet all the criteria for being a planet.
●
Prediction: If Pluto is a dwarf planet, then it should not have cleared its neighborhood of
other similar objects, meaning that there should be other dwarf planets in its vicinity.
●
Test: Scientists used telescopes and spacecraft to observe and measure the properties of
Pluto and other objects in the Kuiper belt, and found that Pluto indeed had many
neighbors that were comparable or larger in size.
●
Conclusion: Based on the evidence, scientists concluded that Pluto should be reclassified
as a dwarf planet, along with other objects that met the same criteria. This decision was
made by the IAU
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
- Access to all documents
- Unlimited textbook solutions
- 24/7 expert homework help