Our Place in the Universe (HKU Common Core Courses)

Our Place in the Universe (HKU Common Core Courses) The University of Hong Kong Common Core Course CCST9012 Our Place in the Universe

Lecture Time: Wednesdays 16:30 - 18:20
Venue: Lecture Theatre P4, LG1/F, Chong Yuet Ming Physics Building

Lecturers:
Professor Sun Kwok
Room G12, Chong Yuet Ming Physics Building (Faculty of Science Office)
Tel: 3917 2682
[email protected]

Dr Jason Pun
Department of Physics
Room 104D, Chong Yuet Ming Physics Building
Tel: 2859 1962
Email: [email protected]

Tutors

Dr Anisia Tang
Room G12, Chong Yuet M

ing Physics Building (Faculty of Science Office)
Tel: 3917 5711
Email: [email protected]

Dr Tim Wotherspoon
Room 316, Hui Oi Chow Science Building
Tel: 3917 5420
Email: [email protected]

Dr Bosco Yung
Room 225, Hui Oi Chow Science Building
Tel: 3917 7851
Email: [email protected]

21/05/2023

The cycles of four seasons over a year has been well known to all humans since the beginning of civilization. By tracing the path of the Sun (the ecliptic) among the stars over the course of a year, the Greeks realized that the plane of the ecliptic is inclined relative to the celestial equator (as determined by the daily rotation of the stars). They realized that this inclination is the cause of the seasons. So the origin of the seasons was known over 2500 years ago.

02/03/2023

If you have not yet seen the Venus-Jupiter conjunction, go out and look west to see the two planets together after sunset.

03/02/2023

Today (February 4) is 立春 (beginning of Spring), the first of the 24 seasonal markers in the Chinese calendar. After the calendar reform of 1670 (時憲曆), 立春 is defined as the date when the Sun is at 315 degrees ecliptic longitude and is almost always on the same date in the Gregorian calendar. For details, see p. 119 of Our Place in the Universe.

20/01/2023

Why do leap months 閏月 mostly occur in the summer?

A leap month occurs when there is no zhongqi 中氣 (12 of the 24 seasonal markers) in the lunar month. After the calendar reform of 1670, the time intervals between the seasonal markers are not longer fixed, but are dependent on the actual movement of the Sun. Since the Sun moves faster in the winter, the time intervals between seasonal markers are shorter, so there is a good chance that a lunar month has one 中氣 zhongqi. In summer, the Sun moves slower, and the chance of leap month 閏月 is higher. Most leap months occur between the 5th and 8th month of the Chinese calendar. This year is unusual as there will be a leap second month beginning on March 22nd 2023.

06/01/2023

Winter solstice 2022 is on December 22 (Hong Kong time). The next new moon is on December 23. The second next new moon is Jan 22. Since the new moon happened so soon after winter solstice, the Chinese New Year is very early this year.

For determination of the Chinese New Year, see Chapter 9 of Our Place in the Universe.

27/09/2022

Venus is a bright object in the sky and often surprises city-dwellers who are not accustomed to looking at the sky. In March 1945, the battleship U.S.S. New York was in the south Pacific when the crew noticed a bright object in the sky. Suspecting that it was a secret Japanese weapon, Captain K.C. Christian ordered the battleship’s anti-aircraft guns to fire at the object. After half an hour with no apparent effect, the firing stopped. The ship’s navigator then figured out that they had been firing at the planet Venus.

In fact, many UFO sightings reported by the public can be attributed to Venus. In one of the most publicized cases, police
officers in 11 counties in the state of Georgia, U.S.A. chased and followed the planet Venus for several days in 1967, believing that it was an UFO.

(Chapter 10, Our Place in the Universe)

27/09/2022

Jupiter is at its brightest in 59 years. Jupiter is in opposition (directly opposite to the Sun as viewed from Earth). This couples with the fact that the Earth and Jupiter are closest to each other in their respective elliptical orbits, makes it appear the brightest.

Because it is in opposition, Jupiter is visible in the night sky from sunset to sunrise, and will be at its highest point in the sky after midnight. It is the brightest object in the sky and you can't miss it.

(On the history of our understanding of planetary motion, see Chapter 10 of Our Place in the Universe).

18/06/2022

The first direct experimental proof of the rotation of the Earth was by Ferdinand Reich in 1831. He detected an eastward deflection of 2.8 cm from a drop of 160 m in a mine, confirming the effect of the Coriolis force. This was 288 years after the publication of the heliocentric theory by Copernicus in 1543.

For details, see Chapter 2 in Our Place in the Universe II: the scientific approach to discovery.

26/05/2022

For 2000 years, we have followed the teaching of Aristotle that heaven is different from earth and celestial objects are physically distinct from the Earth. The work of Kirchoff and Bunsen represented the first challenge of the worldview of Aristotle (Chapter 9, Our Place in the Universe II: the scientific approach to discovery).

17/05/2022

One of the questions on the final exam a few years ago;

3. The philosopher Karl Popper calls Anaximander’s idea that the Earth is a free floating object in space “one of the boldest, most revolutionary, and most portentous ideas in the whole history of human thinking”. What are the observational facts that led Anaximander to propose this hypothesis? (10%)

I did not talk at length about this in class so the question requires some extrapolation on the part of students. I am glad the some students did perfectly on this one.

16/05/2022

There was a total lunar eclipse last night. In 1504, Christopher Columbus was running out of food in Jamaica. So he told the natives that there would be a lunar eclipse on February 29, 1504 and demanded that they provided him with food supplies. The natives were greatly impressed by his successful prediction and gave him what he asked.

Review exercise 44 in "Our Place in the Universe" (vol. I), p. 245: What was the phase of the Moon on that day?

26/03/2022

Most science students have the perception that Copernicus' heliocentric theory is obviously correct, but in fact his theory took more than 100 years before acceptance. Skeptics of the theory cited the absence of observational evidence the orbital motion of the Sun and the self rotation of the Earth. The non-detection of stellar parallax implies that stars must be very far away if the heliocentric model is correct. But stars appeared to have finite apparent sizes. They also cited theoretical objections that if the Earth is moving at high speed, how come we don't feel it? As for Copernicus' theory itself, it is not more accurate than Ptolemy's in predicting future planetary positions but he needs more epicycles than Ptolemy.

All these problems were not resolved until more than 200 years after the death of Copernicus. For details, see Chapters 2-3 of Our Place in the Universe II: the scientific approach to discovery

Address

Hong Kong

Website

Alerts

Be the first to know and let us send you an email when Our Place in the Universe (HKU Common Core Courses) posts news and promotions. Your email address will not be used for any other purpose, and you can unsubscribe at any time.

Contact The University

Send a message to Our Place in the Universe (HKU Common Core Courses):

Shortcuts

Share

Category