13 May 2017:
The telescope is currently at the Johnson’s Space Center in Houston. Testing is underway to see if the telescope will still function at a temperature of almost absolute zero.
Scientists are excited about JWST because it will be the most powerful telescope in space so far. JWST will replace the Hubble Space Telescope, which has been in space for about 27 years. JWST will examine deep space and deep time to see the first galaxies, look for forming planetary systems, and pinpoint exoplanets.
Because JWST will be looking for incredibly cold, far-away objects and events, it has to run at a low temperature itself. This can pose a problem for the equipment.
TRAPPIST-1a, a star about 40 light-years away, became an internet hit in February after NASA announced they had found seven exoplanets obiting around it. This is the most amount of exoplanets we have discovered orbiting a single star, outside of our own solar system, of course.
The planetary system was named after The Transiting Planets and Planetesimals Small Telescope (TRAPPIST) in Chile. Scientists used this telescope to find three of the exoplanets.
From Galileo to NASA, astronomers have used telescopes to examine the stars and planets. Several of the telescopes have been launched into space: these telescopes are not bothered by atmospheric distortion or light pollution.
Having looked up into the night sky myself and felt wonder and curiosity, I am excited for what JWST will bring to the table.
20 May 2017:
A team of scientists at the University of Exeter have been exploring the possibility that Proxima B—an exoplanet orbiting the nearest stars to our solar system—might be habitable. The rash of exoplanets discovered in recent years begs the question: how do astronomers find exoplanets?
Since Neptune was discovered in 1846, astronomers have realized that it is possible to find planets indirectly instead of just through observation (Neptune was discovered because of the gravitational effect it had on Uranus and was observed later).
Radial velocity method: Also known as Doppler spectroscopy. Just as stars exert a gravitational on planets, planets also exert a gravitational pull on stars. It may appear that a planet is orbiting a star, but really, both the planet and the star are orbiting a common center of mass. As a star orbits away from the Earth, the star’s light will red-shift, and as the star orbits closer to Earth its light will blue shift. Earth-sized planets are too small to be easily detected with this method, but as instruments have become more sensitive, even smaller planets have been found.
Transit: This method requires that a planet pass right in front of its star relative to the Earth. Obviously, this isn’t going to happen all the time, but astronomers have instruments sensitive enough that they can detect transiting exoplanets a few thousand light years away. This is how seven exoplanets were detected around TRAPPIST-1 early this year.
Gravitational lensing: This method was predicted by Einstein’s theories. If a luminous object passes directly behind a massive object relative to the Earth, the background object’s light will be bent by the foreground object, creating a lensing effect. The background object’s light will be magnified. If the foreground object is a star with a planet, the planet can be detected by how it contributes to the lensing. This is a complicated process, but there have been exoplanets discovered using this method.
Direct imaging: Considering how long it took the human race to find Uranus and Neptune, you can probably imagine what it’s like to directly observe planets in another solar system. Most exoplanets are imagined using infrared, which means only bigger, hotter planets at a good distance from their star can be imaged.
10 June 2017:
Weighing an object while it is billions of miles away may seem impossible, but scientists are still giving it a go.
Announced just this week, astronomers were able to measure the mass of Stein 2051 B, a white dwarf star about 18 light-years from Earth, using gravitational lensing.
Stein’s companion star, a bright red dwarf, passed behind the white dwarf. “During this transit, the background star appeared to change its position in the sky, moving ever so slightly to the side, even though its actual position on the sky had not changed at all,” according to an article by Scientific American. Using the Hubble Space Telescope, astronomers calculated how massive Stein 2051 B is by how much its companion’s light was deflected.
Gravitational lensing was first theorized by Einstein as part of his theory of general relativity. Einstein thought that objects bent space depending on their mass, and that massive objects could even bend and redirect light.
He also theorized that gravity could be used as a lens to magnify distant objects as massive objects bent light from the object towards the observer.
In 1919, British astronomer Arthur Eddington used a solar eclipse to show that the Sun’s gravity had displaced stars behind it.
The lensing effect Einstein thought about has also been tested. Massive objects can bend the light of objects behind them, creating an effect called an Einstein ring. This is especially helpful if the more distant object is smaller and fainter.
Doing the impossible has been science’s job for a long time now. Even though Einstein’s theories are now well-accepted and tested, but I hope this August’s solar eclipse will be a time to recreate Eddington’s experiment, among others.
24 June 2017:
It’s only now that astronomers are officially confirming the existence of a planet orbiting KELT-9, an star about 616 light-years from Earth.
“We found [KELT-9b] back in 2014, if you can believe it,” Professor Scott Gaudi, from Ohio State University, told BBC news in a June 2017 article. “It took us this long to finally convince ourselves that this truly bizarre and unusual world was in fact a planet orbiting another star.”
KELT-9b has a daytime temperature of more than 7,800 F (4,600 K). This makes it hotter than the surface of most red dwarf stars, which are the most common type of star in the Milky Way.
The surface of KELT-9b is so hot that it is unlikely molecules can survive in its atmosphere.
“This is the hottest gas giant planet that has ever been discovered,” Gaudi said. Gaudi worked on this study with NASA’s Jet Propulsion Labratory.
“KELT-9b is 2.8 times more massive than Jupiter, but only half as dense,” according to JPL. Planets with lower density tend to have a smaller radius, but the heat from its host star has blown the planet’s atmosphere out.
The star is a blue Type-A star. At only 300 million years old, KELT-9 is a young in star years. It is more than twice as large, and almost twice as hot, as the Sun.
Keivan Stassun, a professor of physics and astronomy at Vanderbilt University, said, “KELT-9 radiates so much ultraviolet radiation that it may completely evaporate the planet.”
The JPL article states, “Given that the planet’s atmosphere is constantly blasted with high levels of ultraviolet radiation, the planet may even be shedding a tail of evaporated planetary material like a comet.”
With an orbital period of about 1.5 days and the possibility of it trailing a stream of ejected matter behind it, KELT-9b seems more like a comet than a planet. While we may not be able to learn much about alien life from this exo-planet, KELT-9b is just another example of the variety and possibility that can be found in the universe around us.