Questions:

1. The most common type of star in the universe is the main sequence star. The name comes from the fact that in a graph of a star’s brightness versus its colour, main sequence stars lie along a prominent diagonal band. What is this graph called?

2. The abundance of elements produced in a star increases up to the atomic number of X, and then declines. This is partly because X is the lightest element for whose nuclear fusion produces less energy than it consumes. Name X.

3. When a star of low to medium mass runs out of helium, it will need to fuse carbon, which requires a core temperature of at least 1 billion K. If the star lacks this temperature, its outer layers will be shed, leaving behind an inert core. What is this core called?

4. When the core of a very heavy star collapses due to its own gravity, it can form a neutron star. What is the upper limit of the mass of a neutron star called?

5. For some very heavy stars, scientists have predicted an unusual kind of supernova when they run out of fuel. In this event, the star undergoes a partial collapse, kickstarting a thermonuclear reaction that completely blows up the star. What is such a supernova called?

Visual:

Name this nebula, at whose centre lies a famous pulsating neutron star that greatly advanced scientists’ understanding of how big stars die.

Answers:

1. Hertsprung-Russell diagram

2. Iron

3. White dwarf

4. Tolman-Oppenheimer-Volkoff limit

5. Pair-instability supernova

Visual: Crab Nebula

Questions:

1. A German engineer built the first train powered by electricity in 1879. He also founded a company that is a major electrical engineering multinational corporation today, and his name has been adopted as the SI unit of __________ ___________. Name the engineer and fill in the blanks.

2. In April 1869, George Westinghouse, Jr. received a patent for a braking system that improved on a previous design. The new design revolutionised the railway sector and became the precursor for modern railway brakes. Name the previous design, in which compressed air pushed on a piston, which then applied brake-shoes to multiple wheels.

3. An invention in the 1880s of a device called a trolley pole allowed trolleys, trams, and streetcars to draw power from an overhead electric transmission line. It consisted of a pole atop of the vehicle that would brush against the line as the vehicle moved. Name the modern version of this technology.

4. Thanks to its large reserves of coal, which country was the last in the world to switch all of its locomotives from being steam-powered to being diesel-powered?

5. Achieving a sustainable hydrogen economy is a much-touted goal of many countries. What is the collective name for trains that are powered by hydrogen?

Visual:

Name the train class (pictured above) which set a speed record for a railway vehicle running on conventional tracks in 2007: 574.8 km/hr.

Answers:

1. Werner von Siemens

2. Straight air brake

3. Pantograph

4. China

5. Hydrail

Visual: TGV POS

Questions:

1. Name the German physicist who is widely credited with first studying the general theory of relativity in five dimensions, creating the precursors of some ideas that later appeared in string theory.

2. Name the mathematician who was awarded the Fields Medal in 1998 for explaining ‘monstrous moonshine’, a strange connection between the monster group, a group of relationships used in string theory, and a function in number theory.

3. Name the Indian physicist who was awarded the Breakthrough Prize in Fundamental Physics in 2012 for “opening the path to the realisation that all string theories are different limits of the same underlying theory”.

4. In 1997, an Argentinian string theorist made an unusual mathematical discovery that – very simply speaking – found a way to connect two theories, one that could ‘explain’ gravity and one that couldn’t. Name the theorist.

5. The Indian physicist Abhay Ashtekar is one of the founders of ____ _______ _______, another theory of quantum gravity that, like string theory, tries to unify gravity with quantum mechanics. Fill in the blanks.

Visual:

This image identifies the solution to an ancient problem. Today, it’s a part of enumerative geometry, a branch of maths in which some solutions have been informed by findings in string theory. Name the problem.

Answers:

1. Theodor Kaluza

2. Richard Borcherds

3. Ashoke Sen

4. Juan Maldacena

5. Loop quantum gravity

Visual: Problem of Apollonius

Q: Twilight is the light visible above the horizon when the sun is below the horizon. It is civil twilight when the sun is 6º below the horizon; X twilight when 12º below; and astronomical twilight when 18º below. Name X.

A: Nautical twilight

Q: At astronomical twilight in the evening, Y becomes visible in the sky, and at astronomical twilight in the morning, Y becomes invisible. What is Y?

A: The faintest star visible to the naked eye

Q: An asura in Hindu mythology was slain by one of the avatars of Lord Vishnu at twilight because he had a boon that he couldn’t be slain at day or night. Name the asura.

A: Hiranyakashipu

Q: When the sun is setting behind you, the shadow that earth’s atmosphere casts will be in front of you, near the horizon. At civil twilight, this shadow has a faint pink border. It is sunlight diffracted in earth’s atmosphere. What is this pink belt called?

A: Belt of Venus

Q: During X (in Q1), the sunlight remaining in earth’s atmosphere has a deep blue shade – the result of ozone molecules absorbing light of other frequencies. The absorption is weak, so its effects are pronounced when light has to travel longer through the atmosphere, which happens at twilight. What effect is the absorption called?

A: Chappuis effect

Q: The red fox (Vulpes vulpes), seen here in the U.S. on March 21, 2018, is most active at twilight. What is the adjective that describes such animals?

A: Crepuscular