OrbitalHub

NASA dixit:

“Nate made landfall over the weekend along the northern Gulf Coast as a Category 1 hurricane with sustained winds reported at 85 mph (~140 kph) by the National Hurricane Center (NHC) first at 7:00pm CDT on Saturday October 7th in Louisiana near the mouth of the Mississippi River then again several hours later at 12:30 a.m. CDT on Sunday October 8th near Biloxi, Mississippi before moving quickly moving northward through northern Alabama and central Tennessee.

NASA’s GPM satellite helped track Nate’s progress through the Gulf of Mexico and also captured Nate’s landfall on the north central Gulf Coast. The following animation shows instantaneous rain rate estimates from NASA’s Integrated Multi-satellitE Retrievals for GPM or IMERG product over North America and the surrounding waters beginning on Thursday October 5th when Nate first became a tropical storm near the northeast coast of Nicaragua in the western Caribbean until its eventual landfall on the northern Gulf Coast on Sunday October 8th.

IMERG estimates precipitation from a combination of space-borne passive microwave sensors, including the GMI microwave sensor on board the GPM core satellite, and geostationary IR (infrared) data. The animation shows Nate moving rapidly northward through the Gulf of Mexico on the 7th. Nate’s rapid movement from 20 to as much as 26 mph to strengthen despite being over very warm waters and in a relatively low wind shear environment. Nate reached a peak intensity of 90 mph sustained winds, which it maintained while passing over the Gulf of Mexico, but it did not intensify any further before making landfall. The animation also shows two 3-D flyby’s of Nate captured by the GPM core satellite as it overflew the storm just before landfall at 22:58 UTC (5:58 CDT) on Saturday October 7th and again at 08:42 UTC (3:42 CDT) on Sunday October 8th soon after Nate’s second landfall.

The 3-D precipitation tops (shown in blue) are from GPM’s DPR as are the vertical cross sections of precipitation intensity. The first overpass shows that Nate is a very asymmetric storm with most of the rainbands associated with Nate located north and east of the center. With it’s rapid movement, Nate was unable to fully develop and lacks the classic ring of intense thunderstorms associated a fully developed eyewall. Although overall much the same, the second overpass shows an area of deep, intense convection producing heavy rains over southwest Alabama.

Because of its rapid movement, Nate did not produce the catastrophic flooding that Harvey did. However, Nate is being blamed for 2 storm-related fatalities in the U.S. and at least 38 across Central America, most in Nicaragua and Costa Rica.

GPM is a joint mission between NASA and the Japanese space agency JAXA.”

Video credit: NASA Goddard

NASA dixit:

“Our Cold War history is now offering scientists a chance to better understand the complex space system that surrounds us. Space weather — which can include changes in Earth’s magnetic environment — are usually triggered by the sun’s activity, but recently declassified data on high-altitude nuclear explosion tests have provided a new look at the mechanisms that set off perturbations in that magnetic system. Such information can help support NASA’s efforts to protect satellites and astronauts from the natural radiation inherent in space.”

Video credit: NASA Goddard

NASA dixit:

“No planet is better studied than the one we actually live on. NASA’s fleet of Earth observing spacecraft, supported by aircraft, ships and ground observations, measure aspects of the environment that touch the lives of every person around the world. They study everything from the air we breathe, to rain and snow that provide water for agriculture and communities, to natural disasters such as droughts and floods, to the oceans, which cover 70 percent of Earth’s surface and provide food for many people around the world. Satellites and instruments on the International Space Station circle the whole globe, seeing both where people live and those remote parts of deserts, mountains and the vast oceans that are difficult if not impossible to visit. With instruments in space, scientists can get data for the whole globe in detail that they can’t get anywhere else. This visualization shows the NASA fleet in 2017, from low Earth orbit all the way out to the DSCOVR satellite taking in the million-mile view.”

Music credit: The Glide, by Zubin Thakkar [SOCAN]

Video credit: NASA Goddard

NASA dixit:

“NASA’s CubeSat Launch Initiative provides opportunities for small satellite payloads built by universities, high schools and non-profit organizations to fly on upcoming launches. Through innovative technology partnerships NASA provides these CubeSat developers a low-cost pathway to conduct scientific investigations and technology demonstrations in space, thus enabling students, teachers and faculty to obtain hands-on flight hardware development experience.

Each proposed investigation must demonstrate a benefit to NASA by addressing aspects of science, exploration, technology development, education or operations relevant to NASA’s strategic goals. This initiative provides NASA a mechanism for low-cost technology development and scientific research to help bridge strategic knowledge gaps and accelerate flight-qualified technology.”

Video credit: NASA Kennedy

Wikipedia dixit:

“A solar flare is a sudden flash of brightness observed near the Sun’s surface. It involves a very broad spectrum of emissions, an energy release of typically 1 × 10²⁰ joules of energy for a well-observed event. A major event can emit up to 1 × 10²⁵ joules (the latter is roughly the equivalent of 1 billion megatons of TNT, or over 400 times more energy than released from the impact of Comet Shoemaker–Levy 9 with Jupiter). Flares are often, but not always, accompanied by a coronal mass ejection. The flare ejects clouds of electrons, ions, and atoms through the corona of the sun into space. These clouds typically reach Earth a day or two after the event. The term is also used to refer to similar phenomena in other stars, where the term stellar flare applies.

Solar flares affect all layers of the solar atmosphere (photosphere, chromosphere, and corona), when the plasma medium is heated to tens of millions kelvins, while the cosmic-ray-like electrons, protons, and heavier ions are accelerated to near the speed of light. They produce radiation across the electromagnetic spectrum at all wavelengths, from radio waves to gamma rays, although most of the energy is spread over frequencies outside the visual range and for this reason the majority of the flares are not visible to the naked eye and must be observed with special instruments. Flares occur in active regions around sunspots, where intense magnetic fields penetrate the photosphere to link the corona to the solar interior. Flares are powered by the sudden (timescales of minutes to tens of minutes) release of magnetic energy stored in the corona. The same energy releases may produce coronal mass ejections (CME), although the relation between CMEs and flares is still not well established.

X-rays and UV radiation emitted by solar flares can affect Earth’s ionosphere and disrupt long-range radio communications. Direct radio emission at decimetric wavelengths may disturb the operation of radars and other devices that use those frequencies.

Solar flares were first observed on the Sun by Richard Christopher Carrington and independently by Richard Hodgson in 1859 as localized visible brightenings of small areas within a sunspot group. Stellar flares can be inferred by looking at the lightcurves produced from the telescope or satellite data of variety of other stars.

The frequency of occurrence of solar flares varies, from several per day when the Sun is particularly “active” to less than one every week when the Sun is “quiet”, following the 11-year cycle (the solar cycle). Large flares are less frequent than smaller ones. On July 23, 2012, a massive, and potentially damaging, solar superstorm (solar flare, coronal mass ejection, solar EMP) barely missed Earth, according to NASA. According to NASA, there may be as much as a 12% chance of a similar event occurring between 2012 and 2022, although because this particular figure was based on an extreme extrapolation of the calculated frequency of future storms, the actual probability of this is quite uncertain.”

Video credit: NASA’s Goddard Space Flight Center/Genna Duberstein

Wikipedia dixit:

“A neutron star is the collapsed core of a large (10–29 solar masses) star. Neutron stars are the smallest and densest stars known to exist. Though neutron stars typically have a radius on the order of 10 kilometres (6.2 mi), they can have masses of about twice that of the Sun. They result from the supernova explosion of a massive star, combined with gravitational collapse, that compresses the core past the white dwarf star density to that of atomic nuclei. Most of the basic models for these objects imply that neutron stars are composed almost entirely of neutrons, which are subatomic particles with no net electrical charge and with slightly larger mass than protons. They are supported against further collapse by neutron degeneracy pressure, a phenomenon described by the Pauli exclusion principle. If the remnant has too great a density, something which occurs in excess of an upper limit of the size of neutron stars at 2–3 solar masses, it will continue collapsing to form a black hole.

Neutron stars that can be observed are very hot and typically have a surface temperature around 600000 K. They are so dense that a normal-sized matchbox containing neutron-star material would have a mass of approximately 3 billion tonnes, or a 0.5 cubic kilometre chunk of the Earth (a cube with edges of about 800 metres). Their magnetic fields are between 10⁸ and 10¹⁵ times as strong as that of the Earth. The gravitational field at the neutron star’s surface is about 2×10¹¹ times that of the Earth.

As the star’s core collapses, its rotation rate increases as a result of conservation of angular momentum, hence newly formed neutron stars rotate at up to several hundred times per second. Some neutron stars emit beams of electromagnetic radiation that make them detectable as pulsars. Indeed, the discovery of pulsars in 1967 was the first observational suggestion that neutron stars exist. The radiation from pulsars is thought to be primarily emitted from regions near their magnetic poles. If the magnetic poles do not coincide with the rotational axis of the neutron star, the emission beam will sweep the sky, and when seen from a distance, if the observer is somewhere in the path of the beam, it will appear as pulses of radiation coming from a fixed point in space (the so-called “lighthouse effect”). The fastest-spinning neutron star known is PSR J1748-2446ad, rotating at a rate of 716 times a second or 43,000 revolutions per minute, giving a linear speed at the surface on the order of 0.24 c (i.e. nearly a quarter the speed of light).

There are thought to be around 100 million neutron stars in the Milky Way, a figure obtained by estimating the number of stars that have undergone supernova explosions. However, most are old and cold, and neutron stars can only be easily detected in certain instances, such as if they are a pulsar or part of a binary system. Slow-rotating and non-accreting neutron stars are virtually undetectable; however, since the Hubble Space Telescope detection of RX J185635-3754, a few nearby neutron stars that appear to emit only thermal radiation have been detected. Soft gamma repeaters are conjectured to be a type of neutron star with very strong magnetic fields, known as magnetars, or alternatively, neutron stars with fossil disks around them.

Neutron stars in binary systems can undergo accretion which typically makes the system bright in x-rays while the material falling onto the neutron star can form hotspots that rotate in and out of view in identified X-ray pulsar systems. Additionally, such accretion can “recycle” old pulsars and potentially cause them to gain mass and spin-up to very fast rotation rates, forming the so-called millisecond pulsars. These binary systems will continue to evolve, and eventually the companions can become compact objects such as white dwarfs or neutron stars themselves, though other possibilities include a complete destruction of the companion through ablation or merger. The merger of binary neutron stars may be the source of short-duration gamma-ray bursts and are likely strong sources of gravitational waves. Though as of 2016 no direct detection of the gravitational waves from such an event has been made, gravitational waves have been indirectly detected in a system where two neutron stars orbit each other.”

Video credit: NASA Goddard