Planets

It is true that a star can turn into a planet, but the star has to be a brown dwarf. There are multiple different types of star, all having different properties, but in order for a star to become a planet, it would have to have been a brown dwarf star.Brown dwarfs are stars?Normally, stars …

Thanks to gravity, the earth does fall. It is actually in a constant state of falling since it is in orbit around the sun. This gravitational pull that the sun has on the earth is useful since it stops earth from catapulting into space. Gravity means that objects are not just drawn to the thing …

The truth is, the planets in our solar system never actually line up perfectly. This is something that we think should happen because a lot of the artwork surrounding the solar system sees all of the planets in a perfectly straight line that is just not achievable for our solar system. We are led to …

Light travels about 186,000 miles/sec. in a vacuum. Why this speed, and not some other speed? This is a great, simple, question that touches the heart of modern physics. The simple answer is that we don’t know. The speed of light, c, is one of the “constants of the Universe” that we can measure, that …

Would the constellations we see from Earth look any different from other planets in our solar system? In other words, would the “Big Dipper” still be recognizable as such? Great question! The stars that we see and that make up the constellations are distributed in three dimensions more like blueberries in a muffin than like …

Given the recent discovery of the presence of liquid water on Mars, how likely do you think the possibility of terraforming is? (I know that part’s open-ended, but stick with me.) Can you postulate a method to begin colonization and terraforming simultaneously, or would humans have to wait the (presumed) hundreds—if not thousands—of years for …

Is Pluto still a planet? How can astronomers decide if Pluto is or not a planet? Thank you for your question. It is one that often comes up, and hopefully my response will clarify Pluto’s status. The short answer is no, Pluto is no longer a planet. It is now classified as a type of …

Approximately how long does it take for a planet to be born? Is a planet currently forming and if there is, what is its name? To answer how long it takes for planets to form, we first need to have a look at how planets are formed. The formation of planets is very closely related …

Is it true that there is a policy to not send probes anywhere that conditions might support life? To my knowledge, there is no policy that explicitly prohibits sending a probe to potentially habitable extraterrestrial environments. Mars is a prime example, and probes have been sent there for decades now. It will be something similar …

Is Jupiter a failed star? I study how stars and planets form, which is a big part of the ways that Jupiter both is and isn’t like a star. We can consider Jupiter to look somewhat like a “failed star” because it actually has a chemical composition that is very similar to the Sun. Jupiter …

e most mornings, and I notice and understand how over the course of a year it rises in a different area on the horizon. These position changes having to do with the Earth’s tilt and rotation around the Sun. I also get to see the moonrise and its position change on the horizon, much like …

Is there a way to provide a magnetic field for Mars? Would one even be needed to keep an atmosphere on Mars (if an atmosphere could be thickened on Mars somehow)? It would be a shame to build up an Earth-like global warming on Mars to release its carbon dioxide into its atmosphere, only for …

What is the evidence that early astronomers used to show that the Earth is turning on its axis (or was it a growing understanding)? That’s a great question! Some of the early Greeks proposed that the Earth rotated on its axis to explain the apparent daily motions of the Sun and other stars in the …

About 100 tons of cosmic dust falls on the Earth everyday, and this has been happening for billions of years, making the Earth heavier. Why doesn’t this cause our orbit around the Sun to change? The orbit of the planets is determined by the total mass in the system, and the dominant mass is that …

The New Horizons eclipse photo of Pluto shows the atmosphere as a blue ring, while a similar picture of Earth would show ours with a red hue. What causes the difference since they both have a nitrogen atmosphere? Thank you for your question. It’s a good one! You are correct in that the primary constituent …

If the collision hypothesis about the formation of the Moon is correct, why is there no ring of debris around Earth? Surely the residual debris were not all swept up by the gravity of the Earth and the Moon. The collision hypothesis for the formation of the Moon (also known as the Giant Impact hypothesis) …

Is there public domain software that can calculate the trajectory of a spacecraft using a model of the solar system (that includes planets and moons)? Is it feasible for a group of high-school students to develop such a model for a fun (non-school, non-graded) project? The idea is to develop a model that would determine …

Why does only one side of the Moon face the Earth? Synchronized rotations would not last so long. There must be some force holding this pattern in place. Could it be that the center of gravity of the Moon is not in the middle of the Moon? One side of the Moon always faces the …

Seeing the Earth circles the sun and our Moon circles the Earth, why would a comet or asteroid, passing closer to Earth than the Moon, maintain its orbit and not get captured into Earth’s orbit? The reason, quite simply, is one of speed. The comet or asteroid is moving too fast to be captured into …

What proof do you have that planets are made from gas and dust? The main way we study what planets are made of is by looking at their birthplaces around other stars. Planet formation happens in what are called “protoplanetary disks”. These protoplanetary disks are made of material leftover from the formation of the central star. …

Does a sunset in the west and a moonrise in the east ever happen at exactly the same time? Yes, a sunset and moonrise can occur at about the same time. Specifically, it occurs on the night of a full moon! Let’s convince ourselves of why this is… Whenever we think about sunrises/sunsets in relation …

If X-ray and radio beams can emit from black holes and the like in interstellar space, can lower frequency waves on the middle to low end of the spectrum be emitted from high-powered beams on Earth and then detected by telescopes – like a sub pinging to its target – in order to search for …