Category Archives: Astronomy

E Is for ´╗┐Europa

Even though the A to Z Challenge is over, and I took a huge break, I’m going to finish it. A lot has happened over the last couple months, but it’s back! Today is the letter E, and I’m talking about Jupiter’s moon Europa! Did you learn anything new?

  1. Europa is the fourth largest natural satellite of Jupiter.
  2. It was discovered in 1610 by Galileo Galilei, along with the other three Galilean satellites.
  3. The surface of Europa is the smoothest surface of any world in the Solar System, consisting of water ice.
  4. Europa orbits Jupiter in just 3.55 days, with one side always facing Jupiter, as it’s tidally locked.
  5. Beneath the ice crust is an estimated 100 km deep ocean of salt water. But it isn’t clear if the ice is thick or thin. However, the amount of water on Europa is about two to three times the volume of Earth’s oceans.
  6. Europa has a weak magnetic field, best explained by Europa’s salt water ocean.
  7. Tidal heating from the interactions of Europa with Jupiter and the other Galilean satellites warms the interior of the moon, possibly resulting in hydrothermal vents at the floor of the ocean. This has led scientists to suggest that life may exist in Europa’s ocean.
  8. Europa most likely has an iron core and a rocky mantle.
  9. Observations by the Hubble Space Telescope provide further evidence of subsurface oceans, as plumes of water have been seen erupting to 200 km above the surface.
  10. Europa has an oxygen atmosphere. But it’s very thin, providing a surface pressure of only 0.1 micropascals.

Let me know what you learned in the comments section below!

A Is for Alpha Centauri

Here it is! It’s the Blogging from A to Z April Challenge! Two years ago, I participated in it, and now I’m doing it again. This time, I have a science theme, and I am featuring videos.

For the first topic, we have Alpha Centauri. Check out the video below. After the video, the facts are available for you to read.

  1. It’s a triple star system 4.37 ly from the sun.
  2. Alpha Centauri A is also known as Rigil Kentaurus, while Alpha Centauri C is known as Proxima Centauri. B has no other name.
  3. Alpha Centauri A is a G2 yellow dwarf star similar to the sun, although 10% brighter and 23% larger.
  4. Alpha Centauri B is a K1 orange dwarf star 90% the mass and 14% smaller radius than the sun.
  5. Proxima Centauri is an M6 class red dwarf star with 0.123 solar masses.
  6. Proxima Centauri orbits the AB pair at a massive distance of 15,000 AU or 0.24 light years, though it’s not completely certain it is a member of the system.
  7. Discovered in 2012, Alpha Centauri Bb was an extrasolar planet that was found in 2015 to be an artefact of data analysis. It doesn’t exist.
  8. In 2016, Proxima Centauri b was announced. It’s an extrasolar planet a bit larger than the earth, but is in the star’s habitable zone. It’s likely to be tidally locked, making life difficult to take hold. It’s also likely to be one of the easiest extrasolar planets to study in the near future because of it’s proximity.
  9. The Alpha Centauri system is estimated to be between 4.5 and 7 billion years old, around the same age of our sun or older.
  10. Due to Proxima Centauri being a flare star, life may never have a chance to become established on b because the flares may strip the planet of its atmosphere.

Coming on Monday is the letter B, which will have a more biological topic. Comments are always welcome!

TRAPPIST-1: A Solar System of Earth-Sized Planets

The announcement that NASA hinted about being a major discovery related to planets orbiting another star turned out to actually be pretty major. In many cases, we’ve seen announcements of huge planets, single Earth-sized planets, or a super-Earth in the habitable zone around a star. This time, it’s even more significant.

TRAPPIST-1 is a very cool and small red dwarf star 39 light years away. Not only does it have one Earth-sized planet, but it has seven. And it’s not just one of them in the habitable zone, it’s three. How’s that for amazing?

Two were originally discovered by The Transiting Planets and Planetesimals Small Telescope (TRAPPIST) in Chile, then confirmed by NASA’s Spitzer Telescope. But Spitzer discovered a further five planets. When the James Webb Space Telescope is in operation, it will be used to study these planets even further. We may be able to discover the atmospheric composition, determining if they’re potentially habitable.

As these are planets orbiting a red dwarf, they are close to the star, with the outer planet having an orbital period of only 20 days. This means that they’re likely to be tidally locked, with one side of each planet facing the star. They don’t have enough information about the outer planet to determine its exact size, but scientists guess that it may be icy.

NASA released this video on the planets:

What do you think of this news? Let’s talk about it in the comments section below.

Planetarium Software

I found some really good free planetarium software. It’s called Stellarium. Today, I was able to use this software, but I’m going to download it and use it at home.

You see, I’m going to be using this software at work extensively. This should give you an idea about what I’m going to be doing. When I said I’ll be using my university degree in my job, I meant it. I’ll be educating people on astronomy and physics. But that’s not all. There’s something else I’m not telling you, and I think that will remain a secret for now. Sorry!

What I’ve been able to do with this software is look at stars, nebulae, galaxies, planets, and the Moon. I’ve looked at the movement of Jupiter’s moons over time, watched the Moon’s phases, and examine the night sky around 100,000 years in the past and future. There’s a lot more I can do, and I’ll explore it as much as I can before I start using it at work.

I’ve said it before, and I’ll say it again: I’m finally using my university degree in a job! Do you use your degree in your job?

Plumes Spotted on Europa

Take a look at this image.

Credits: NASA/ESA/W. Sparks (STScI)/USGS Astrogeology Science Center
Credits: NASA/ESA/W. Sparks (STScI)/USGS Astrogeology Science Center

Just what is this? Well, it’s Europa superimposed on an image of Europa taken by the Hubble Space Telescope. See that white stuff coming from the bottom left? That seems so similar to what we’ve seen from Enceladus. That’s a possible water plume!

So, what does this mean? It means that water is making it to the surface of Europa. This also means that we may have a much easier time accessing the water than we thought. We already have an extremely good idea about the internal structure of Europa, which likely includes a very deep liquid water ocean. Europa is one of the best candidates for life in the solar system, and with upcoming missions to Europa and the other icy moons of Jupiter coming soon, we’ll have an excellent opportunity to know what the composition of this water is. It’s suspected to be salty, but how salty is it? And does it support life?

This is very exciting. What do you think?

Proxima Centauri b – Our Newest Neighbour

This is the biggest exoplanet news ever. 4.25 light years away, a tiny red dwarf star has revealed something extremely important: a potentially Earth-like planet. The ESO announced today that they have discovered a planet orbiting the nearest star to our solar system, Proxima Centauri.

Artist's impression of Proxima Centauri b. Credit: ESO/M. Kornmesser. Source.
Artist’s impression of Proxima Centauri b. Credit: ESO/M. Kornmesser. Source.

So, how big is this planet? At least 1.3 times the size of Earth, or possibly up to 3 Earths. This would mean it’s either an Earth-like planet or a Super Earth. It is most likely to be terrestrial and due to its proximity to its star, it’s tidally locked. One side always faces its star. However, it’s in that very special place in a star’s orbit where liquid water can exist. That’s the good thing. The bad thing is that ultraviolet and X-rays from Proxima Centauri could make the surface of the planet potentially uninhabitable. With that being said, life could thrive below the surface.

What would it be like on the planet, though? The side facing the star would be hot and blasted by radiation. The side facing away from the star would probably be extremely cold, possibly covered in ice. The area that’s perpetually at sunset would be the most habitable and comfortable. If there’s a significant atmosphere, then temperatures could be stabilised all around the planet, and likely to be a constant wind flowing from the day side to the night side.

Breakthrough Starshot, a project started by billionaire Yuri Milner, physicist Stephen Hawking, and others, now has a destination. This project, designed to send tiny probes at 20% the speed of light into interstellar space, could reach Proxima Centauri b in only 20 years, then another 4.25 years to transmit data back to the Earth. The probes would take pictures and send them back. However, the estimated launch date is 2060, so many of us today would unlikely get to see this. Well, I plan to be around in 2084. I’ll only be 107 years old. I want to see this planet!

This has a lot of people excited, including me. I really want to know more about this planet. I wish we could go now. To see the surface of a world orbiting another star would be the dream of any astronomer or astronomy enthusiast. This is big!