Space and astronomy news
We spent 5 episodes telling the story of astronomy so far, how we got from the work of the Babylonians to the modern discoveries made in the last decade. But now we want to look forward, studying the current space missions and experiments to uncover the mysteries that astronomers hope to solve.
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Many of the modern ideas in astronomy happened in just the 20th century: dark matter, the Big Bang, inflation, quasars, black holes. So many discoveries in one important century.
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Is this a window into the interior of the Moon, and an entrance to a potential future lunar habitat? The Lunar Reconnaissance Orbiter Camera has taken a closer look at what is thought to be a skylight into a lava tube in the Mare Ingenii (The Sea of Cleverness) region, one of the few lunar mare features on the far side of the Moon. This skylight is huge — about 130 meters (427 feet) in diameter — and is probably the result of a partially collapsed lava tube. But lunar geologists really weren’t expecting to see this kind unusual feature in this region. Previously, a skylight, or open pit was found in the Marius Hills region in the Ocean of Storms on the near side which is filled with volcanic domes and rilles where a lava tube might form. However, those kinds of volcanic features are not found in Mare Ingenii. LRO will definitely be taking additional looks at this pit.
The Japanese SELENE/Kaguya spacecraft first discovered this irregularly-shaped hole, visible in the top image at LROC’s 0.55 m/pixel resolution. The boulders and debris resting on the floor of the pit are partially illuminated (left side of the pit) and probably originated at the surface, falling through the pit opening during collapse.
This could be an important find for several reasons. Lava tubes are important in understanding how lava was transported on the early moon, but they could also provide a home to future human explorers. This one on the far side would be a great place to set up a base for future telescopes proposed for observations out into the Universe from the Moon’s far side. The Moon’s surface is a harsh place, the human body doesn’t do well when exposed to the constant radiation present on the Moon’s atmosphere-less environment. Long term human presence would work if astronauts could spend most of their time shielded underground. While excavating a hole large enough to fit an entire moon colony in it would be a huge engineering challenge, these lava tubes could provide ready-made locations for a well-shielded base.
Read our previous article about the pit in the Marius Hills.
Here’s a look at a huge lava tube in Hawaii. It looks almost man-made, but is a natural feature created by volcanism:
How lava tubes form: when lava flows out onto the surface, it cools on top and may form a solid roof. The roof insulates the still-liquid lava below it, allowing it to continue to flow, sometimes for several kilometers. At the end of the eruption, the lava can drain completely out of the tube, leaving a hollow remnant of the flow that forms an underground cavern. This tube, called Thurston Tube, is about 3 meters in height.
Sources: LROC website, Planetary Blog
The new VISTA telescope at the Paranal Observatory in Chile (the Visible and Infrared Survey Telescope for Astronomy) has captured a great new image of the Sculptor Galaxy (NGC 253), and this video allows you to zoom in for a closer look. The sequence starts with a wide view of the southern sky far from the Milky Way. Only a few stars are visible, but then VISTA brings us in closer where the view shifts to the very detailed new infrared image of NGC 253 provided by the new telescope at Paranal. By observing in infrared light VISTA’s view is less affected by dust and reveals a myriad of cooler stars as well as a prominent bar of stars across the central region. The VISTA image provides much new information on the history and development of the galaxy. See the still image below.
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The Sculptor Galaxy (NGC 253) lies in the constellation of the same name and is one of the brightest galaxies in the sky. It is prominent enough to be seen with good binoculars and was discovered by Caroline Herschel from England in 1783. NGC 253 is a spiral galaxy that lies about 13 million light-years away. It is the brightest member of a small collection of galaxies called the Sculptor Group, one of the closest such groupings to our own Local Group of galaxies. Part of its visual prominence comes from its status as a starburst galaxy, one in the throes of rapid star formation. NGC 253 is also very dusty, which obscures the view of many parts of the galaxy. Seen from Earth, the galaxy is almost edge on, with the spiral arms clearly visible in the outer parts, along with a bright core at its center.
Learn more about this image and the VISTA telescope at the ESO website.
Planet Earth, which we humans and all currently-known forms of life call home, is the third planet from the Sun, and the largest of the terrestrial planets. With a mean radius of 6,371 km (3,958.8 miles), it is slightly larger than Venus (which has a radius of approx. 6,050 km), almost twice the size of Mars (~3,390 km), and almost three times the size of Mercury (~2,440 km).
Basically, Earth is a pretty big world. But just how big if one were to measure it from end to end? If one were to just start walking, how many kilometers (and/or miles) would they have to go before they got back to where they started. Well, the short answer is just over 40,075 km (or just over 24,901 miles). But as always, things get a little more complicated when you look closer.
Here’s this week’s Where In The Universe Challenge. You know what to do: take a look at this image and see if you can determine where in the universe this image is from; give yourself extra points if you can name the instrument responsible for the image. We’ll provide the image today, but won’t reveal the answer until tomorrow. This gives you a chance to mull over the image and provide your answer/guess in the comment section. Please, no links or extensive explanations of what you think this is — give everyone the chance to guess.
UPDATE: The answer has now been posted below.
This is Pingualuit Crater in northern Quebec, on Earth. It was first seen by a crew from a United States Army Air Force plane in 1943, and was one of the first craters in this region to be identified as an impact crater. This image was taken by NASA’s Landsat 7 satellite on August 17, 2002. In this image, water appears blue, and land appears in varying shades of beige. The high latitude of the area limits vegetation, so thick, lush forests do not flourish in this region. In fact, the crater’s name derives from an Inuktitut term for cold-weather-induced skin blemishes.
Read more about Pingualuit Crater at the NASA Earth Observatory website.
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There’s a new eye on the skies on the lookout for ‘killer’ asteroids and comets. The first Pan-STARRS (Panoramic Survey Telescope & Rapid Response System) telescope, PS1, is fully operational, ready to map large portions of the sky nightly. It will be sleuthing not just for potential incoming space rocks, but also supernovae and other variable objects.
“Pan-STARRS is an all-purpose machine,” said Harvard astronomer Edo Berger. “Having a dedicated telescope repeatedly surveying large areas opens up a lot of new opportunities.”
“PS1 has been taking science-quality data for six months, but now we are doing it dusk-to-dawn every night,” says Dr. Nick Kaiser, the principal investigator of the Pan-STARRS project.
Pan-STARRS will map one-sixth of the sky every month and basically be on the lookout for any objects that move over time. Frequent follow-up observations will allow astronomers to track those objects and calculate their orbits, identifying any potential threats to Earth. PS1 also will spot many small, faint bodies in the outer solar system that hid from previous surveys.
“PS1 will discover an unprecedented variety of Centaurs [minor planets between Jupiter and Neptune], trans-Neptunian objects, and comets. The system has the capability to detect planet-size bodies on the outer fringes of our solar system,” said Smithsonian astronomer Matthew Holman.
Pan-STARRS features the world’s largest digital camera — a 1,400-megapixel (1.4 gigapixel) monster. With it, astronomers can photograph an area of the sky as large as 36 full moons in a single exposure. In comparison, a picture from the Hubble Space Telescope’s WFC3 camera spans an area only one-hundredth the size of the full moon (albeit at very high resolution).
This sensitive digital camera was rated as one of the “20 marvels of modern engineering” by Gizmo Watch in 2008. Inventor Dr. John Tonry (IfA) said, “We played as close to the bleeding edge of technology as you can without getting cut!”
Each image, if printed out as a 300-dpi photograph, would cover half a basketball court, and PS1 takes an image every 30 seconds. The amount of data PS1 produces every night would fill 1,000 DVDs.
“As soon as Pan-STARRS turned on, we felt like we were drinking from a fire hose!” said Berger. He added that they are finding several hundred transient objects a month, which would have taken a couple of years with previous facilities.
Located atop the dormant volcano Haleakala (that’s Holy Haleakala to you, Bad Astronomer) Pan-STARRS exploits the unique combination of superb observing sites and technical and scientific expertise available in Hawaii.
Source: CfA
This week’s Carnival of Space is hosted by Peter Lake over at AstroSwanny’s ArtScope Blog, complete with a personal Carnival of Space Geo Greeting! (It’s very cool!)
Click here to read the Carnival of Space #158.
And if you’re interested in looking back, here’s an archive to all the past Carnivals of Space. If you’ve got a space-related blog, you should really join the carnival. Just email an entry to [email protected], and the next host will link to it. It will help get awareness out there about your writing, help you meet others in the space community – and community is what blogging is all about. And if you really want to help out, let Fraser know if you can be a host, and he’ll schedule you into the calendar.
Finally, if you run a space-related blog, please post a link to the Carnival of Space. Help us get the word out.
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“What type of planet is Mars?” is a question that many readers ask. Mars is one of the four terrestrial planets. Mercury, Venus, and Earth are the other three. All of the terrestrial planets are made up of rock and metals. The remaining planets are classified as the outer gas giants.
All of the terrestrial planets have the same basic structure: core, mantle, crust; although each layer differs in thickness depending on the planet. Mercury has an average density of 5.43 g/cm3. Earth is the only planet more dense than Mercury. Mercury most likely has a liquid core that is mostly an iron-nickel alloy. The core accounts for as much as three-fourths of the planet’s radius. There are no numbers available for how thick the mantle and core are. Venus has a crust that extends 10-30 km below the surface. After that, the mantle reaches to a depth of some 3,000 km. The planetary core is a liquid iron-nickel alloy. Average planet density is 5.240 g/cm3.
Even though we live on Earth, not everyone is aware of its density and the depth of the various layers of our home world. The crust thickness averages 30 km for land masses and 5 kilometers for seabeds. The mantle extends on to an additional depth of 2,900 km. The core begins at a depth of around 5,100 km and is in two distinct parts: the outer core of liquid iron-nickel alloy and the inner core which is a solid alloy of iron-nickel. Average planet density is 5.520 g/cm3. The final terrestrial planet is Mars. Mars is roughly one-half the diameter of Earth, which leads scientists to speculate that the core has cooled and solidified. The depth of the crust and mantle are not known for sure, but the average planet density is 3.930 g/cm3. While there are only four terrestrial planets in our Solar System, here is a report on how NASA is trying to find more in other star systems.
Since we are talking specifically about Mars, we will talk about the composition of the planet’s surface material. There are hundreds of volcanoes on the surface of Mars. Several are regarded as the tallest mountains in the Solar System. Without plate tectonics, these volcanoes erupted for millions of years. Those massive eruptions explain why the entire surface is covered in basalt that is high in iron content. The iron content in the basalt has interacted with the Martian atmosphere and oxidized. The iron oxide explains why the entire Martian surface is coated in a reddish dust.
Answering ”what type of planet is Mars” took us on a little bit of a tangent. Hopefully, it is a tangent that will inspire you to find out more about the Red Planet.
We have written many articles about Mars for Universe Today. Here’s an article about the gravity on Mars, and here’s an article about the size of Mars.
If you’d like more info on Mars, check out Hubblesite’s News Releases about Mars, and here’s a link to the NASA Mars Exploration home page.
We’ve also recorded an episode of Astronomy Cast all about Mars. Listen here, Episode 52: Mars.
Source:
NASA
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Venus is the second planet from the Sun, and a virtual twin of our own planet Earth in many ways. But what type of planet is Venus? There are two major classifications of planets in the Solar System. There are the inner, rocky terrestrial planets and then the outer gas giants. Venus is a terrestrial planet.
The terrestrial planets are the 4 inner rocky worlds in the Solar System: Mercury, Venus, Earth and Mars. The word terrestrial comes from the root term “terra”, which is Latin for Earth. So the terrestrial planets are “Earth like” worlds.
And Venus is the most Earth-like planet in the Solar System. It has almost the exact same size, mass and density. Its composition is probably very similar to Earth, with a metallic core surrounded by a rocky mantle and a thin crust. The main difference between Earth and Venus is the incredibly thick carbon dioxide atmosphere, which raises temperatures on the surface of Venus to the point that it’s hot enough to melt lead.
But compare a terrestrial world like Venus to the gas giants like Saturn and Jupiter. The mean density of Venus is 5.204 g/cm3. While the density of Saturn is only 0.687 g/cm3. The density of Saturn is less than water, and it would float if you could find a pool large enough.
We’ve written many articles about Venus for Universe Today. Here’s an article about pictures of planet Venus, and here’s an article about how to find Venus in the sky.
If you’d like more info on Venus, check out Hubblesite’s News Releases about Venus, and here’s a link to NASA’s Solar System Exploration Guide to Venus. Finally, here’s a link to ESA’s Venus Express spacecraft.
We have also recorded an entire episode of Astronomy Cast all about Venus. Listen here, Episode 50: Venus.