‘Time Dilation’ in Early Universe

Time Dilation

Context:

Scientists used observations of quasars to demonstrate time dilation in the early universe, showing how time then passed only about a fifth as quickly as it does today.

Key Findings:

  • Continual expansion of the universe –
    • Responsible for the slower passage of time in the past compared to the present.
    • The observations stretch back to about 12.3 billion years ago.
  • Previous Observations –
    • Time dilation dating back around 7 billion years based on observations of supernovas, stellar explosions.
    • Brightness of these quasars was compared to that of quasars existing today, showing certain fluctuations about a fifth as quickly as it does today.

A supernova is the biggest explosion that humans have ever seen. Each blast is the extremely bright, super-powerful explosion of a star.

What is Time dilation?

  • It is the slowing of time as perceived by one observer compared with another, depending on their relative motion or positions in a gravitational field.
  • It is a consequence of Einsteinian theory of relativity that showed that time and space are intertwined and that universe has been expanding outward in all directions since the Big Bang.
  • It occurs because objects with a lot of mass create a strong gravitational field. Stronger the gravity, more space-time curves, and the slower time itself proceeds.

What are Quasars?

  • Tremendously active supermassive black holes millions to billions of times more massive than our sun, usually residing at centers of galaxies.
  • Characteristics –
    • Draws matter towards them through strong gravitational forces
    • Emits powerful radiation and high-energy particle jets
    • Surrounded by a glowing disk of matter
    • Brightness remains observable from the early stages of the universe

Consider the following phenomena:

  1. Light is affected by gravity.
  2. The Universe is constantly expanding.
  3. Matter warps its surrounding space-time.

Which of the above is/are the prediction/predictions of Albert Einstein’s General Theory of Relativity, often discussed in media?

[UPSC Civil Services Exam – 2018 Prelims]

  • 1 and 2 only
  • 3 only
  • 1 and 3 only
  • 1, 2 and 3

Source: The Hindu

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