Cosmic Journeys explores the challenges of interstellar flight and the technological possibilities that may one day send us on a long voyage out into the galaxy. What imperatives will define the mission when it launches and finally arrives: exploration and science, or a struggle for survival?
Category Archives: Learn Science
What is space? What is Space Made of ? If you ignore the galaxies, stars & atoms, then the rest of empty space is mysterious. It is really not nothing. See this documentary to know more.
It seems very simple but actually there is more to this.
Most scientists believe the Moon’s formation resulted from a giant impact between the Earth and a mysterious object called Theia.
The Real Reality Show: Does Dark Energy Hold the Fate of the Cosmos? This mysterious force makes up most of the universe and dictates its ultimate destiny.
Black holes are gravitational behemoths that dramatically twist space and time. Recently, they’ve also pointed researchers to a remarkable proposal—that everything we see may be akin to a hologram. Alan Alda joins Kip Thorne, Robbert Dijkgraaf and other renowned researchers on an odyssey through one of nature’s most spectacular creations, and learn how they are leading scientists to rewrite the rules of reality.
NASA astronaut Reid Wiseman or otherwise known as @Astro_Reid recounts his launch into space on a Soyuz rocket and his stay on board the International Space Station as a member of Expedition 40/41 from the Moving Beyond Earth Gallery at the Smithsonian’s Air and Space Museum. During his 165 days in space, took all of us back on Earth along for the journey. An active Twitter user, Wiseman posted amazing images and videos from space, using the hashtag #EarthArt for many of his amazing shots of our beautiful planet.
A pulsar (portmanteau of pulsating star) is a highly magnetized, rotating neutron star that emits a beam of electromagnetic radiation. This radiation can only be observed when the beam of emission is pointing toward the Earth, much the way a lighthouse can only be seen when the light is pointed in the direction of an observer, and is responsible for the pulsed appearance of emission. Neutron stars are very dense, and have short, regular rotational periods. This produces a very precise interval between pulses that range from roughly milliseconds to seconds for an individual pulsar.
The events leading to the formation of a pulsar begin when the core of a massive star is compressed during a supernova, which collapses into a neutron star. The neutron star retains most of its angular momentum, and since it has only a tiny fraction of its progenitor’s radius (and therefore its moment of inertia is sharply reduced), it is formed with very high rotation speed. A beam of radiation is emitted along the magnetic axis of the pulsar, which spins along with the rotation of the neutron star. The magnetic axis of the pulsar determines the direction of the electromagnetic beam, with the magnetic axis not necessarily being the same as its rotational axis. This misalignment causes the beam to be seen once for every rotation of the neutron star, which leads to the “pulsed” nature of its appearance. The beam originates from the rotational energy of the neutron star, which generates an electrical field from the movement of the very strong magnetic field, resulting in the acceleration of protons and electrons on the star surface and the creation of an electromagnetic beam emanating from the poles of the magnetic field. This rotation slows down over time as electromagnetic power is emitted. When a pulsar’s spin period slows down sufficiently, the radio pulsar mechanism is believed to turn off (the so-called “death line”). This turn-off seems to take place after about 10–100 million years, which means of all the neutron stars in the 13.6 billion year age of the universe, around 99% no longer pulsate. The longest known pulsar period is 8.51 seconds.
The precise periods of pulsars make them useful tools. Observations of a pulsar in a binary neutron star system were used to indirectly confirm the existence of gravitational radiation. The first extrasolar planets were discovered around a pulsar, PSR B1257+12. Certain types of pulsars rival atomic clocks in their accuracy in keeping time. .
During the Astro Camp some of you had queries regarding Gamma Ray Bursts and also about hyper novae and black holes. Watch this documentary to give you more info on this.
It was one of the greatest mysteries in modern science: a series of brief but extremely bright flashes of ultra-high energy light coming from somewhere out in space. These gamma ray bursts were first spotted by spy satellites in the 1960s. It took three decades and a revolution in high-energy astronomy for scientists to figure out what they were.
All those who have attended the Astronomy Camp at DPS Tapi have seen many stars and constellations. If you remember I had shown you one star in the Constellation Perseus called Algol. Algol is a binary star. Learn more about Binary stars in this video from Kurdistan Planetarium.
Scientists have been reconstructing the history of the moon by scouring its surface, mapping its mountains and craters, and probing its interior. What are they learning about our own planet’s beginnings? Decades ago, we sent astronauts to the moon as a symbol of confidence in the face of the great cold war struggle. Landing on the moon was a giant leap for mankind. But it’s what the astronauts picked up from the lunar surface that may turn out to be Apollo’s greatest legacy.
When the astronauts of Apollo stepped out of their landing craft, they entered a world draped in fine sticky dust, strewn with rocks, and pocked with craters. They walked and rambled about, picking up rocks that they packed for the return flight. Back in earth-bound labs, scientists went to work probing the rocks for clues to one of the most vexing questions in all of science. Where did the moon come from? The answer promised to shed light on an even grander question. Where did Earth come from? And how did it evolve into the planet we know today?
The nature of the moon began to come into focus four centuries ago. Galileo Galilei had heard of an instrument built by Dutch opticians capable of “seeing faraway things as though nearby.” Galileo, in many ways the first modern scientist, saw this new instrument as a tool to help settle a long standing question. What was the nature of the heavens, and how did the world of men fit within it? To some philosophers, the moon was a perfect, crystalline sphere of divine substance, free of Earth’s imperfections. Galileo, with his telescope, saw a more familiar reality. He noted mountains and valleys on the moon, features like those of Earth.
The astronauts of Apollo lifted off on a series of missions to get a close up look at the moon and perhaps settle the debate. Because there’s no atmosphere there, the astronauts entered landscapes that are nearly frozen in time. They could scour the lunar surface for evidence of events going back almost to the time of its birth.
Indeed, eons of impacts had opened up the Moon’s interior, leaving a wealth of information strewn about their landing sites. Scientists had already noticed that some large old craters were surrounded by concentric rings. You can see one of the most pronounced examples in this image of the Mare Orientale, captured recently by NASA’s Lunar Reconnaissance Orbiter, or LRO. The colors show differences in elevation.
The old view was that the impact had melted the rock below. A newer view held that the impactor had actually splashed down on a molten surface. That gave rise to the radical notion that, early in its history, the moon’s surface was covered in a vast ocean of magma. When the astronauts arrived, they found relatively light rocks known as anorthosites. Their presence suggested that heavier material had sunk toward the moon’s interior, forcing lighter material to the surface. The rocks they brought back were found to be strikingly similar to those on Earth, in part because they share forms of oxygen, called isotopes, that scientists regard as “blood types” for solar system bodies. Then there was this. The moon appeared to be completely, utterly, dry, with no evidence that water was ever present on its surface.
NASA’s Orion spacecraft launched successfully atop a United Launch Alliance Delta IV Heavy rocket Dec. 5 at 7:05 a.m. EST from Space Launch Complex 37 at Cape Canaveral Air Force Station in Florida. Orion’s Exploration Flight Test-1 (EFT-1), is the first flight test for NASA’s new deep space capsule and is a critical step on NASA’s journey to Mars. The 4.5 hour flight is scheduled to conclude with the splashdown of Orion in the Pacific Ocean.
The testing of ORION – NASA’s Deep Space Exploration Spacecraft has been postponed once again. This video explains in detail NASA’s new deep space exploration spacecraft called Orion which will take humans farther into space than ever before including landing on an asteroid, the moons of Mars, and Mars itself.
It is commonly theorized that the universe began with the Big Bang 13.7 billion years ago. But since we can only see as far as light has traveled in that time, we can’t actually make out the edge of the universe. Could it be that the universe is infinite? Is there any way to find out what the shape of the universe really is? Can we find the edge, discover what might lie beyond it, and perhaps even discover a universe next to ours? Narrated by Morgan Freeman
14th Isaac Asimov Memorial Debate conducted by the American Museum of Natural History hosted by the Director of the Hayden Planetarium and Celebrity Astrophysicist Neil deGrasse Tyson. He welcomes a distinguished panel of scientist to discuss and debate the Existence of Nothing. Panelists include Richard Gott, Lawrence Krauss, Eve Silverstein, Jim Holt and Charles Seife. This is a great debate watch till the end.
The details in this video are as of 2009. I have posted it only for you to compare the sizes and get an idea of scale. The largest star identified as of now is UY Scuti. Click here for the complete list from Wikipedia.
VY Canis Majoris (VY CMa) is a red hypergiant star located in the constellation Canis Major. With a size of 2600 solar radii, it is the largest known star and also one of the most luminous known. It is located about 1.5 kiloparsecs (4.6×1016 km) or about 4,900 light years away from Earth. Unlike most stars, which occur in either binary or multiple star systems, VY CMa is a single star. It is categorized as a semiregular variable and has an estimated period of 6,275,081 days, or just under 17,200 years.
Antares is a red supergiant star in the Milky Way galaxy and the sixteenth brightest star in the nighttime sky (sometimes listed as fifteenth brightest, if the two brighter components of the Capella quadruple star system are counted as one star). Along with Aldebaran, Spica, and Regulus it is one of the four brightest stars near the ecliptic. Antares is a variable star, whose apparent magnitude varies from +0.9 to +1.8.
The Pistol Star is a blue hypergiant and is one of the most luminous known stars in the Milky Way Galaxy. It is one of many massive young stars in the Quintuplet cluster in the Galactic Center region. The star owes its name to the shape of the Pistol Nebula, which it illuminates. It is located approximately 25,000 light years from Earth in the direction of Sagittarius. It would be visible to the naked eye as a fourth magnitude star, if it were not for the interstellar dust that completely hides it from view in visible light.
Rigel (β Ori / β Orionis / Beta Orionis) is the brightest star in the constellation Orion and the sixth brightest star in the sky, with visual magnitude 0.18. Although it has the Bayer designation “beta”, it is almost always brighter than Alpha Orionis (Betelgeuse).
Aldebaran (α Tau, α Tauri, Alpha Tauri) is an orange giant star located about 65 light years away in the zodiac constellation of Taurus. With an average apparent magnitude of 0.87 it is the brightest star in the constellation and is one of the brightest stars in the nighttime sky. The name Aldebaran is Arabic (الدبران al-dabarān) and translates literally as “the follower”, presumably because this bright star appears to follow the Pleiades, or Seven Sisters star cluster in the night sky. This star is also called the Bull’s Eye because of its striking orange color and its location in the bull’s head shaped asterism. NASA’s Pioneer 10 spacecraft, which flew by Jupiter in 1973, is currently traveling in the direction and will reach it in about two million years.
Arcturus (α Boo / α Boötis / Alpha Boötis) is the brightest star in the constellation Boötes. With a visual magnitude of −0.05, it is also the third brightest star in the night sky, after Sirius and Canopus. It is, however, fainter than the combined light of the two main components of Alpha Centauri, which are too close together for the eye to resolve as separate sources of light, making Arcturus appear to be the fourth brightest. It is the second brightest star visible from northern latitudes and the brightest star in the northern celestial hemisphere. The star is in the Local Interstellar Cloud.
Pollux (β Gem / β Geminorum / Beta Geminorum) is an orange giant star approximately 34 light-years from the Earth in the constellation of Gemini (the Twins). Pollux is the brightest star in the constellation, brighter than Castor (Alpha Geminorum). As of 2006, Pollux was confirmed to have an extrasolar planet orbiting it.
Sirius is the brightest star in the night sky. With a visual apparent magnitude of −1.46, it is almost twice as bright as Canopus, the next brightest star. The name Sirius is derived from the Ancient Greek Σείριος. The star has the Bayer designation α Canis Majoris (α CMa, or Alpha Canis Majoris). What the naked eye perceives as a single star is actually a binary star system, consisting of a white main sequence star of spectral type A1V, termed Sirius A, and a faint white dwarf companion of spectral type DA2, termed Sirius B.
The Sun is the star at the center of the Solar System. The Sun has a diameter of about 1,392,000 kilometres (865,000 mi) (about 109 Earths), and by itself accounts for about 99.86% of the Solar System’s mass; the remainder consists of the planets (including Earth), asteroids, meteoroids, comets, and dust in orbit. About three-fourths of the Sun’s mass consists of hydrogen, while most of the rest is helium.
The Universe in a Nutshell: The Physics of Everything
Michio Kaku, Henry Semat Professor of Theoretical Physics at CUNY
What if we could find one single equation that explains every force in the universe? Dr. Michio Kaku explores how physicists may shrink the science of the Big Bang into an equation as small as Einstein’s “e=mc^2.” Thanks to advances in string theory, physics may allow us to escape the heat death of the universe, explore the multiverse, and unlock the secrets of existence. While firing up our imaginations about the future, Kaku also presents a succinct history of physics and makes a compelling case for why physics is the key to pretty much everything.
New telescopes come with a couple different types of inexpensive finders – magnifying and non-magnifying ones. In this video, David Fuller of “Eyes on the Sky” takes the viewer through the various types of basic finders, highlighting the benefits and drawbacks of each so the viewer can make a better educated decision when purchasing a new telescope. Also covered is how to align a finderscope with the main telescope, with a visual demonstration of how it might look for the viewer.
Barlow lenses are an inexpensive – and often effective – way to increase the magnification and eyepiece collection of amateur astronomers. In this video, David Fuller of “Eyes on the Sky” takes the viewer through the various types, caveats and benefits with using them, as well as what to look for when shopping for one.
This video about the basics of telescopes discusses field of view, in particular, the difference between apparent field of view (AFOV) and telescopic field of view (TFOV). With an explanation of the math used to calculate these plus various examples of the calculations and visuals, the viewer can finish this video with a more complete understanding of this concept that is often confusing to beginning amateur astronomers who are new to telescopes.
Hosted by David Fuller of “Eyes on the Sky,” this video goes over the various sizes and types of basic eyepieces for many amateur telescopes. The three most common eyepiece barrel diameters are discussed, as well as the types of lens configurations which determine how well the eyepiece forms an image for the user – including the concept of eye relief which can matter a lot to those who wear eyeglasses. Discussed are Huygens, Ramsden, Kellner, RKE, Modified Achromat, Plossl and some advanced designs, plus some information about anti-reflection coatings. An excellent primer for anyone wanting to understand more about telescope eyepieces.