Explanation

Astronomers estimate a star’s age primarily by analyzing its chemical composition—especially the presence of hydrogen and helium.

Older stars generally have fewer heavy elements.  

Explanation

Glacier grooves are scratches or grooves on rocks caused by rocks embedded in moving glaciers.

They are formed parallel to the direction of glacier movement.

Explanation

A supernova is a massive and powerful explosion of a dying star.

It is one of the brightest events in the universe, releasing huge amounts of energy.

Explanation

The temperature increases with an increase in Pressure in a closed system, or in specific atmospheric layers like the stratosphere or thermosphere.

Explanation

• Red stars, also known as red dwarfs, typically have a surface temperature around 3000°C (5400°F).
• This is the coolest temperature range for stars, and it's what gives them their distinctive red color.

Explanation

A refracting telescope has two lenses:

1. A primary lens (objective) that collects and focuses light.
2. A secondary lens (eyepiece) that magnifies the focused light to form an image.

Explanation

• In a mercury thermometer, the mercury in the bulb expands and rises in the tube, which has a linear scale ranging from 94°F to 108°F.
• This specific range is commonly used for medical thermometers to measure human body temperature.

Explanation

• Atmospheric pressure is a scalar quantity that acts equally in all directions, pressing on surfaces from all sides.
• This is why a balloon expands in all directions when inflated, and why a submarine is squeezed from all sides by the surrounding water pressure.

Explanation

The Moon is a natural satellite that orbits the Earth.

It reflects sunlight, providing light at night and affecting tides.

Explanation

• When the Moon and the Sun are on the same side of the Earth, we see a New Moon.
• This occurs when the Moon is between the Earth and the Sun, making the side of the Moon facing the Earth unilluminated.