Astronomy
Happy 25th birthday! Five Reasons the Hubble Space Telescope is Awesome
On April 24 1990, the Hubble Space Telescope was launched into low Earth orbit on board the Space Shuttle Discovery, and deployed the next day. Named after Edwin Hubble, one of the great astronomers of the 20th century, this amazing instrument has offered us hugely important insights into our universe, not to mention some of the most iconic images of outer space ever captured. Even today, after 25 years, Hubble is one of the most famous and most important space telescopes out there. In order to celebrate this great milestone, here’s the story of the legendary telescope in five amazing facts about it.
First of all, the Hubble Space Telescope was a trailblazer. Famed astrophysicist Lyman Spitzer was one of the first to propose an astronomical observatory in space, far from our planet’s thick atmosphere, all the way back in 1946. Then, throughout the 1960s and 1970s he actively lobbied for the development of what would become the Hubble Space Telescope. After a series of delays due to various issues like funding difficulties and the Challenger disaster, Hubble was finally sent into orbit in 1990. Over the next thirteen years, it would be followed by three more powerful telescopes, part of NASA’s Great Observatories program: the Compton Gamma Ray Observatory (1991), the Chandra X-ray Observatory (1999), and the Spitzer Space Telescope (2003). Though all of them have provided scientists with valuable data regarding the Universe, none has even come close to the public profile of Hubble.
Soon after deployment however, a significant problem was discovered. Instead of the sharpest images of space ever taken, scientists were receiving low-quality, blurred photos. The error was eventually found to be a flaw in the 2.4-meter primary mirror, on the order of 2,200 nanometers (about a 50th of the thickness of a sheet of paper). Called a spherical aberration, the flaw meant that the light bouncing off the center of the mirror wouldn’t focus in the same place as the light reflected off the edge. Though the problem was well understood and could be corrected in “post-production,” it was a costly and time-consuming process. Which brings us to the second reason Hubble is awesome: it wears the most expensive pair of glasses of all time!
In December 1993, the first of five servicing missions was launched, which among others contained the Corrective Optics Space Telescope Axial Replacement, or COSTAR. This massive device was about the size of a phone booth and contained a series of mirrors designed to correct the aberration. The cost of the mission was a hefty $500 million, or about a third of the cost of the entire telescope at launch – but it was a complete success and Hubble finally started sending images of the quality scientist had expected all along.
Soon afterwards, scientists got busy using their new toy. The impact of Hubble on the scientific community is difficult to overstate. In its first decade in orbit, 8% of citations to the top-cited astronomy papers were based on Hubble data. Well into the first decade of the 21st century, Hubble Space Telescope papers were being cited tens of thousands of times per year, making it one of the most important scientific instruments in the world.
And it’s not like the data is about some very narrow aspects of astronomy, only professionals would be interested in. Data from Hubble has been used for a whole host of highly significant discoveries, related to everything from the birth of stars and planets, to the evolution of galaxies, measurements of exoplanets and gamma-ray bursts, and observations of gigantic black holes which we now know lurk within the centers of most galaxies. Not only that, but Hubble’s observations of Cepheid variable stars and distant supernovas have provided important insights regarding the rate of expansion of the Universe. The data gathered from the telescope, alongside other ground-based instruments, have led astronomers to believe the expansion of the Universe is accelerating (instead of slowing down, as previously thought). This remarkable finding has actually earned a group of scientists the 2011 Nobel Prize in Physics, and has led others to suggest the existence of dark energy to explain it.
But Hubble wasn’t just a highly advanced plaything for professional astronomers. For one thing, at least in the first few years, amateur astronomers could apply for usage of its instruments. But a lot more significantly, NASA soon started taking incredibly beautiful pictures of the Universe, and releasing them to the public. For the first time, perhaps, since the moon landing, the general public could also fully appreciate the work that was being carried out by astronomers. And this is the final point I would like to make about the Hubble Space Telescope: more than any other scientific instrument, it has shown us how awesome the Universe really is. Images like the iconic Pillars of Creation or the Hubble Deep Field are not only relevant to the trained eye of the astronomer, but are also, well, beautiful – more akin to works of art than the cold, dry results of science. No other telescope, not the Large Hadron Collider, nor the International Space Station have managed to captivate the imagination of the public quite like Hubble, and the glimpses it has offered us into the workings of our spectacular Universe.
The Hubble Space Telescope has long outlasted its initial service duration estimates. Over the years, five service missions have been deployed to correct flaws and upgrade instruments, so even after a quarter of a century Hubble is still going strong – in fact, it’s more powerful than ever, and is expected to be fully operational at least until 2020. Here’s hoping it’s going to be a long and productive journey!
Astronomy
Witness the rare celestial event of Mars and Jupiter reaching their closest proximity in the sky this week, a phenomenon that will not occur again until 2033.
Mars and Jupiter will be only 0.3 degrees apart in the sky on August 14. From our point of view, this passage is very close. If you miss it, you won’t be able to see another one until 2033.
When two objects pass each other in the sky from our point of view, this is called a conjunction. Every time two planets came together, the closer one would block out the other because they would all be moving in a perfectly flat plane. The orbits of the planets are slightly different from those of the other planets, though, so they move slightly to the north and south of each other. Every time, that gap is a different size.
When two things happen close together, the results are especially stunning. Jupiter and Saturn were close enough to each other in 2020 that they could be seen in the same field of view through a telescope. This is a treat for people who like to observe the sky.
Being 0.5 degrees wide, the full moon will fit in any view that can hold the whole moon. This pair will also look good before and after the full moon.
But even with the naked eye, a close conjunction can make the sky look even more amazing. The contrast between the red of Mars and the white of Jupiter will be especially striking. However, Mars’ brightness changes a lot. When it’s at its brightest, it’s about the same brightness as Jupiter. Right now, it’s 16 times less bright. They are so bright that, unless there are clouds, you should be able to see them from all but the dirtiest cities.
Most people in the world will miss this sight, though, because they can’t see the pair of planets in the evening from anywhere on Earth. The exact time they rise depends on where you live, but it’s usually between midnight and 3 am. To see this, you will mostly need to get up before astronomical twilight starts so that you have time to get through the thickest part of the atmosphere.
For people in Europe, Africa, west Asia, and the Americas, the closest time will be 14:53 UTC, which is during the day. The mornings before and after, though, will look almost as close.
Mars and Jupiter meet about every two and a half years, but the most recent one was almost twice as far away and could only be seen in the morning. In 2029, the gaps will be just under two degrees. The next one will be even wider, at more than a degree.
When planets are close to each other, that doesn’t always mean that their distance from each other is very small. Mars has been around the Sun for 687 days, but it is now less than 100 days past its perihelion, which means it is closer than usual. Even though Jupiter is a little closer than usual, it’s not really that close. To be as close as possible to each other, Mars has to be at its farthest point, and Jupiter has to be at its closest point. So this one is not unusual.
But if you want to see something beautiful, you will have to wait more than nine years to see it again.
Astronomy
It may not be long before we find “Earth’s Twin”
To figure out if there is life in other parts of the universe, we start with Earth, where there is life now. Finding another Earth is a good way to find aliens. We have found more than 5,000 exoplanets, but we haven’t found Earth’s twin yet. This could change soon, though. Here comes the PLATO mission from the European Space Agency (ESA).
What does PLATO stand for? It stands for PLAnetary Transits and Oscillations of stars. Its goal is very clear. It will look for nearby stars like the Sun that might have habitable worlds like Earth.
“One of the main goals is to find a way to compare Earth and the Sun.” The size of Earth is in the habitable zone of a star like the Sun. “We want to find it around a star that’s bright enough that we can really figure out how heavy it is and how big it is,” Dr. David Brown from the University of Warwick told IFLScience. “If you like, that’s our main goal.”
The telescope is not only an observatory for looking for planets, but it is also an observatory for collecting data on a huge number of stars. The mission team thinks that the fact that it can do both is a key part of why this telescope will be so important.
“You have two parts of the mission.” One is exoplanets, and the other is the stars. “From a scientific point of view, I think it’s pretty cool that these two parts are working together to make the best science we can,” Dr. Brown said.
One of the secondary goals is to make a list of all the planets that are Earth-like and all the star systems that are out there. One more goal is to find other solar systems that are like ours. Even though we don’t know for sure if our little part of the universe is truly unique, it does seem to be different from everything else.
Dr. Brown told IFLScience, “We have a bunch of other scientific goals.” “Really, how well do we know how planetary systems change and grow over time?” Planetary systems are something we’re trying to understand as a whole, not just one planet at a time.
PLATO is different in more ways than just the goals. It is not just one telescope. In fact, it’s made up of 26 different ones. Two of the cameras are fast, and the other 24 are normal cameras set up in groups of six with a small gap between them. This makes the telescope work better, has a wider field of view, and lets you quickly rule out false positives.
It can be hard to tell which of the things you find when you transit exoplanets are real and which ones are not. With the help of several telescopes, we were able to block out some of the mimics that we would have seen otherwise. “Plus, it looks pretty cool,” Dr. Brown said with excitement. “This big square with all of these telescopes pointing at you looks really cool!”
This week, Dr. Brown gave an update on PLATO at the National Astronomy Meeting at the University of Hull. The telescope is being put together and has recently passed important tests. There are no changes to the planned launch date for December 2026. An Ariane 6 rocket, the same kind that made its first launch last week, will take off from French Guiana.
Astronomy
You can watch and listen to gravitational waves coming from everywhere in the universe
Gravitational waves can be turned into sound very easily. The little chirp changes into little sounds as soon as the blocks hit each other. One of those chirps is my ringtone when my phone has sound, which doesn’t happen very often. The people at Audio Universe have now made the gravitational wave data even better.
In a 3D video, the sounds of gravitational waves hit you from the direction in the sky where it is thought they came from. The sound effects and visualization are both great. There are tiny vibrations in space-time that can hit you as you move your mouse, phone, or VR headset.
Like other sonification projects, it gives blind and visually impaired people a way to get involved in astronomy. It works well with other methods like the Tactile Universe. But that’s not the only reason why they do it.
“We want to do this for three reasons.” It helps researchers look into big, complicated datasets with lots of dimensions. It could be used to make educational materials that are immersive and interesting. Rose Shepherd from Newcastle University says, “It can also make astronomy easier for more people to understand, which is an important thing.” “Making things easier to get makes them better for everyone.”
Being able to listen to the emission lines of celestial objects is one of the most interesting things about sonification for research. As an object moves, its light spectrum peaks spread out, and sonification can make something that is barely noticeable to the eye seem very clear to the ear.
This is helpful in more than one field, though. The group has thought about how adding sound to different datasets could make them better. Warming Stripes is a cool example of this. This is a simple image that shows changes in temperature over time by using a series of stripes, from blue to red. The stripes on the right side get redder as we move from the left to the right. The left side shows decades ago. It is great to see how the climate crisis is getting worse, and now sound adds a little more to it.
“By adding sounds, it can give your data an emotional meaning.” Shepherd explained, “You can use that to show the data how you feel.” “We didn’t mean for the Warming Stripes sonification to make people feel stressed, but it was interesting to see how they reacted instead of just watching the video.”
Audio Universe is making a sonic toolkit that many people can use to make their own resources.
She gave a talk about the audio universe at the National Astronomy Meeting at the University of Hull this week.
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