As always, the Hubble Space Telescope is looking to the stars for new exciting sights. Images of swirling galaxies are extremely common. On June 3, 2019, the Hubble Space Telescope released this photo of two exoplanets orbiting a distant star―an incredibly uncommon sight.
The system is called PDS 70 and is located in the constellation Centaurus. Less massive but larger than our sun, the star, also called V1032 Centauri, is a K5 type. K5 stars are cooler and dimmer than our sun. PDS 70 is 370 light-years from the Earth. That’s over 2.17 quadrillion (2,170,000,000,000,000) miles (3.5 quadrillion kilometers)!
In the image below, the white star represents the location of V1032 Centauri. To the left is PDS 70 b and to the right is PDS 70 c.
Exoplanets PDS 70 b and c. Source: ESO and S. Haffert (Leiden Observatory)
Right now, the only way astronomers know how to find planets is by observing the light from the stars. If there is a regular periodic dip in the signal, astronomers can infer that something is passing in front of it. Anything large enough to do this is probably a planet. While this is helpful, a measurement taken from this far leaves lots of room for error.
These planets were first imaged using the Very Large Telescope in Chile. We know that PDS 70 b is 4 to 17 times as massive as Jupiter, while PDS 70 c is 1 to 10 times as massive. The large range in these estimates is a consequence of the lack of precision in the measurement.
Astronomers are rarely able to get images like this because the stars are so big and bright and the planets are small and dim. Star light completely conceals anything coming from a distant planet. In the image above, astronomers cancelled light from the star to reveal the planets.
Once again, the Hubble Space Telescope dazzles us with the cosmos. We will have to wait to see what new sights they excite us with next time!
Almost every child has dreamed of being an astronaut. We look up at the stars and wonder what’s up there. While not everyone will be an astronaut, there are other ways to get your name to space.
NASA has announced a public engagement campaign in which anyone can submit their name to be sent to Mars. The names will be etched onto a chip and sent with NASA’s Mars 2020 rover. The names will be written “smaller than one-thousandth the width of a human hair”, according to NASA.
So far, over 4 million names have been submitted. A single chip can hold over a million names, but I think it’s safe to assume that NASA will be sending more than one chip with the rover.
Everyone who submits their name will receive a “boarding pass” for a flight to Mars. This boarding pass is, of course, for fun, and not a ticket to the Red Planet. It also “awards” frequent flyer points.
Anyone who wants to submit their name has until the end of September to do so. To submit your name, click here.
The rover will launch in July/August 2020 because Mars and the Earth will be close to each other. When they’re closer together, it takes less fuel, time, and money to launch. Therefore, these “close approaches” are simply the best time to launch.
Artist concept of the Mars 2020 rover. Source: NASA/JPL-CalTech
This rover’s main research will be regarding potential life on Mars. The rover will drill into the Martian surface to collect rock and dirt samples. These samples will be set aside, potentially to be brought to Earth in the future. In addition, the rover will look for organic compounds in the rocks. Other functions include testing an oxygen-production method and looking for subsurface water.
NASA’s Mars 2020 rover is going to allow us to understand the Red Planet’s history as well as we understand the Earth’s. In addition, scientists are hoping to answer questions about the possibilities of humans residing on Mars. That goal, however, is a long way away. NASA has recently announced plans to land humans on the Moon by 2024. This is a huge step towards Mars, but the Moon is considerably closer than Mars. Right now, the plan is to land humans on Mars in the 2030s.
Slowly but surely, humanity is going to Mars. It’ll be an exciting thing to watch. Click here for more information on Mars 2020.
Ah, Pluto. Everyone’s favorite (dwarf) planet. For some reason unbeknownst to the general public, scientists stripped Pluto of its planetary status in 2006. Many Millennials seem to feel personally attacked for this demotion. They dramatically claim that losing Pluto is like losing a member of our interplanetary family.
Unfortunately, scientists are right. Pluto is not a planet.
Discovering Pluto
In the 1840s, scientists noticed that Uranus’ orbit was inconsistent with predictions from the physics they knew of at that time. Using math, they concluded that another planet must be out there. Scientists pointed their telescopes to the sky and found Neptune. Even after finding Neptune, many felt that another planet must be out there because Neptune didn’t seem to solve all the problems with Uranus’ orbit. Since it had worked once before, they once again pointed their telescopes to the stars. And they found something.
The arrow points to a dot that moves separately from the background stars. This dot is Pluto. From the Lowell Observatory.
Scientists noticed something that was not a far away star—something close. Something orbiting the Sun. They assumed they had found a new planet because astronomers didn’t yet understand the structure of our solar system. They thought that Pluto was much larger and much farther away. However, as time went by, they calculated an increasing small mass for Pluto.
Eventually, astronomers realized the calculations that led to Pluto’s discovery were wrong. There were no problems with Uranus’ orbit. And even if there was, Pluto’s tiny mass wouldn’t account for this difference.
As time went by, astronomers found more Pluto-like objects in the outer solar system, including Eris. A dwarf planet discovered in 2003, Eris is more massive than Pluto (although a little smaller). This forced astronomers to re-evaluate their definition of a planet.
Defining a Planet
In 2006, scientists gathered at The International Astronomy Union’s General Assembly and tackled the question plaguing astronomy at the time: what defines a planet? They decided that a planet must do three things:
1. Orbit a star.
Pluto does this. Check.
2. Be massive enough to hold itself together in a round shape.
Pluto does this too. Check.
3. Dominate its neighborhood.
Pluto does NOT do this. Pluto lies in a portion of the solar system known as the Kuiper Belt, a region that contains small icy bodies, like a second asteroid belt.
Pluto’s orbit, seen in yellow, goes right through the Kuiper Belt. The planets’ orbits, which are white, each trace out their own area. Source: nasa.gov
To be fair, Pluto is a fairly large object for it part of the Solar System; it’s the second most massive non-planet orbiting the Sun. That being said, some moons are larger than Pluto. Looking at the image above, Pluto definitively does not dominate its neighborhood. Scientists ultimately demoted Pluto (and Eris) to a “dwarf planet.”
More evidence
Tilt with the ecliptic
All eight of our planets lie within the same plane of the solar system called the ecliptic plane. However, Pluto is 17 degrees off of this plane. The only other planet to be off the ecliptic is Mercury, but this difference is easily explained by General Relativity. So the question remains: how did Pluto get off the ecliptic?
Pluto’s orbit is vary different from the others. Source: nasa.gov
One theory is that Pluto may have collided with another object, knocking it out of the plane. Another theory is that Pluto may be a captured satellite from a different solar system. Either way, this orbital tilt is very weird for a planet, but quite normal for a Kuiper Belt object.
Charon and Pluto
Another damning piece of evidence comes from Pluto’s moon, Charon. Charon’s mass is about one-eighth of Pluto’s mass, which is relatively large for a moon. For comparison, our moon is only 1.2 percent of the Earth’s mass. This giant moon doesn’t actually orbit Pluto; instead, Pluto and Charon orbit a spot in between them, outside of either body.
Charon, on the left, is quite large for a moon. Pluto, on the right, is the object that Charon Orbits. Taken by the New Horizons Spacecraft. Source: nasa.gov
Some feel that Charon and Pluto should be considered a binary system. However, Charon’s official classification is one of Pluto’s Satellites.
It is important to note that Pluto’s moons don’t make it a planet. 87 Pluto-like objects are also known to have moons. Also, not all planets have moons; Mercury and Venus don’t.
Sorry folks, Pluto is not a planet
When you look at all the evidence, it’s clear that Pluto isn’t a planet. Pluto was only considered a planet because we didn’t know what our solar system looked like. Once we learned more, we needed to reclassify certain objects. That’s what science is all about—learning and adapting.
Pluto didn’t change, it’s official classification did. This, of course, doesn’t mean that we should forget about Pluto. There is still much Pluto can tell us about our solar system; that’s why scientists continue to study the dwarf planet. However, to say that Pluto is as important in the solar system as the planets is completely false. Regardless of what we call it, Pluto is undoubtedly one of the most loved objects in the solar system.
madison brewer 