What factors cause parts of the Earth to have seasonal changes in weather?

What factors cause parts of the Earth to have seasonal changes in weather?

The changing distance between the Sun and Earth over the period of a year.

The changing length of day versus night, and the changing angle at which sunlight strikes the planet.

The changing speed of the Earth in orbit and the changing angle at which sunlight strikes the planet.

The changing speed of the Earth in orbit and the changing distance between the Sun and Earth.

Not counting the Sun, what is the brightest star in the sky as seen from Earth?

Polaris.

Vega.

Sirius.

Altair.

In 1066 King Harold of England saw something in the sky and considered it a sign of very bad luck. What was it?

A supernova.

A meteor storm.

Comet Halley.

A total solar eclipse.

Imagine a Universe where the average density of luminous matter is only 2% of the critical density, HOWEVER there is 1000 times as much dark matter as luminous matter in that Universe. What would be the ultimate fate of such a Universe? Assume there is no such thing as 'dark energy' driving the expansion.

That Universe will stop expanding and re-contract, and will end at some time in the future in a "big crunch."

That Universe will continue to expand with increasing expansion rate and will become cold and dark.

That Universe will remain static.

That Universe will expand forever with a gradually decreasing expansion rate, and become cold and dark.

Light coming to us from across the Universe is subject to gravitational lensing. Which of the following is likely as a result?

Most galaxies appear twice in images as a result of lensing by the intervening mass in relatively nearby galaxies.

The light was repeatedly "bent" by local perturbations to spacetime curvature, caused mostly by clumps of dark matter associated with nearer galaxies.

As the light traversed the Universe, it traveled in "straight lines" and objects are where they appear to be.

Light from distant galaxies is blue-shifted as a result of passing in the vicinity of dark matter.

What is the primary evidence that a large asteroid impact is associated with the extinction of the dinosaurs?

No evidence has been found, it is a completely unsubstantiated claim.

A world-wide layer of iridium which appears to have been created about 65 million years ago.

A 180 degree reversal of the Earth's magnetic field at the end of the Cretaceous period.

Several giant craters all around the planet.

If Earth had had formed without the moon, which of the following statements would be most correct?

The Earth would be spinning fast, with larger tidal swings in its oceans, and life would bedistributed similarly to the present.

The Earth would be spinning faster than now, with smaller, uniform tidal swings in its oceans, and the distribution and forms of life on Earth might be very different.

The Earth would be spinning extremely slowly compared with now, with very long days and nights.

The Earth would look pretty much as it does today, only with smaller tidal swings in its oceans.

Why does Mars appear red?

Carbon dioxide.

Iron oxide.

Sulfur dioxide.

Iron sulfate.