The Planets And Their Respective Sizes Compared To Our Sun.

What Is The Smallest Possible Distance In The Universe?

“At present, there is no way to predict what’s going to happen on distance scales that are smaller than about 10-35 meters, nor on timescales that are smaller than about 10-43 seconds. These values are set by the fundamental constants that govern our Universe. In the context of General Relativity and quantum physics, we can go no farther than these limits without getting nonsense out of our equations in return for our troubles.

It may yet be the case that a quantum theory of gravity will reveal properties of our Universe beyond these limits, or that some fundamental paradigm shifts concerning the nature of space and time could show us a new path forward. If we base our calculations on what we know today, however, there’s no way to go below the Planck scale in terms of distance or time. There may be a revolution coming on this front, but the signposts have yet to show us where it will occur.”

If you went down to smaller and smaller distance scales, you might imagine that you’ll start to see the Universe more clearly and in higher resolution. You’ll be able to hone in on the fundamental properties of nature, and glean more information the deeper you go. This is true, but only up to a point. Beyond that, you start running into the inescapable quantum rules that govern the Universe, and that means there’s a fundamental scale at which our best laws of physics cannot be trusted any longer.

That scale is the Planck scale, and for distances, it corresponds to about 10^-35 meters. It really is a problem for physics, and it’s high time you understood why.

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10 Things: CubeSats — Going Farther

Now that the MarCOs — a pair of briefcase-sized interplanetary CubeSats — seem to have reached their limit far beyond Mars, we’re looking forward to an expanding era of small, versatile and powerful space-based science machines.

Here are ten ways we’re pushing the limits of miniaturized technology to see  just how far it can take us.

1. MarCO: The Farthest (So Far)

MarCO, short for Mars Cube One, was the first interplanetary mission to use a class of mini-spacecraft called CubeSats.

The MarCOs — nicknamed EVE and WALL-E, after characters from a Pixar film — served as communications relays during InSight’s November 2018 Mars landing, beaming back data at each stage of its descent to the Martian surface in near-real time, along with InSight’s first image.

WALL-E sent back stunning images of Mars as well, while EVE performed some simple radio science.

All of this was achieved with experimental technology that cost a fraction of what most space missions do: $18.5 million provided by NASA’s Jet Propulsion Laboratory in Pasadena, California, which built the CubeSats.

WALL-E was last heard from on Dec. 29; EVE, on Jan. 4. Based on trajectory calculations, WALL-E is currently more than 1 million miles (1.6 million kilometers) past Mars; EVE is farther, almost 2 million miles (3.2 million kilometers) past Mars.

MarCO-B took these images as it approached Mars in November 2018. Credit: NASA/JPL-Caltech

2. What Are CubeSats?

CubeSats were pioneered by California Polytechnic State University in 1999 and quickly became popular tools for students seeking to learn all aspects of spacecraft design and development.

Today, they are opening up space research to public and private entities like never before. With off-the-shelf parts and a compact size that allows them to hitch a ride with other missions — they can, for example, be ejected from the International Space Station, up to six at a time — CubeSats have slashed the cost of satellite development, opening up doors to test new instruments as well as to create constellations of satellites working together.

CubeSats can be flown in swarms, capturing simultaneous, multipoint measurements with identical instruments across a large area. Sampling entire physical systems in this way would drive forward our ability to understand the space environment around us, in the same way multiple weather sensors help us understand global weather systems.

Ready to get started? Check out NASA’s CubeSats 101 Guide.

Engineer Joel Steinkraus uses sunlight to test the solar arrays on one of the Mars Cube One (MarCO) spacecraft at NASA’s Jet Propulsion Laboratory. Credit: NASA/JPL-Caltech

3. Measuring Up

The size and cost of spacecraft vary depending on the application; some are the size of a pint of ice cream while others, like the Hubble Space Telescope, are as big as a school bus.

Small spacecraft (SmallSats) generally have a mass less than 400 pounds (180 kilograms) and are about the size of a large kitchen fridge.

CubeSats are a class of nanosatellites that use a standard size and form factor.  The standard CubeSat size uses a “one unit” or “1U” measuring 10x10x10 centimeters (or about 4x4x4 inches) and is extendable to larger sizes: 1.5, 2, 3, 6, and even 12U.

The Sojourner rover (seen here on Mars in 1997) is an example of small technology that pioneered bigger things. Generations of larger rovers are being built on its success.

4. A Legacy of Small Pathfinders

Not unlike a CubeSat, NASA’s first spacecraft — Explorer 1 — was a small, rudimentary machine. It launched in 1958 and made the first discovery in outer space, the Van Allen radiation belts that surround Earth. It was the birth of the U.S. space program.

In 1997, a mini-rover named Sojourner rolled onto Mars, a trial run for more advanced rovers such as NASA’s Spirit, Opportunity and Curiosity.

Innovation often begins with pathfinder technology, said Jakob Van Zyl, director of the Solar System Exploration Directorate at NASA’s Jet Propulsion Laboratory. Once engineers prove something can be done, science missions follow.

5. Testing in Space

NASA is continually developing new technologies — technologies that are smaller than ever before, components that could improve our measurements, on-board data processing systems that streamline data retrievals, or new methods for gathering observations. Each new technology is thoroughly tested in a lab, sometimes on aircraft, or even at remote sites across the world. But the space environment is different than Earth. To know how something is going to operate in space, testing in space is the best option.

Sending something unproven to orbit has traditionally been a risky endeavor, but CubeSats have helped to change that. The diminutive satellites typically take less than two years to build. CubeSats are often a secondary payload on many rocket launches, greatly reducing cost. These hitchhikers can be deployed from a rocket or sent to the International Space Station and deployed from orbit.

Because of their quick development time and easy access to space, CubeSats have become the perfect platform for demonstrating how a new technological advancement will perform in orbit.

RainCube is a mini weather satellite, no bigger than a shoebox, that will measure storms. It’s part of several new NASA experiments to track storms from space with many small satellites, instead of individual, large ones. Credit: UCAR

6. At Work in Earth Orbit

A few recent examples from our home world:

RainCube, a satellite no bigger than a suitcase, is a prototype for a possible fleet of similar CubeSats  that could one day help monitor severe storms, lead to improving the accuracy of weather forecasts and track climate change over time.

IceCube tested instruments for their ability to make space-based measurements of the small, frozen crystals that make up ice clouds. Like other clouds, ice clouds affect Earth’s energy budget by either reflecting or absorbing the Sun’s energy and by affecting the emission of heat from Earth into space. Thus, ice clouds are key variables in weather and climate models.

Rocket Lab’s Electron rocket lifts off from Launch Complex 1 for the NASA ELaNa19 mission. Credit: Trevor Mahlmann/Rocket Lab

7. First Dedicated CubeSat Launch

A series of new CubeSats is now in space, conducting a variety of scientific investigations and technology demonstrations following a Dec. 17, 2018 launch from New Zealand — the first time CubeSats have launched for NASA on a rocket designed specifically for small payloads.

This mission included 10 Educational Launch of Nanosatellites (ELaNa)-19 payloads, selected by NASA’s CubeSat Launch Initiative:

CubeSat Compact Radiation Belt Explorer (CeREs) — High energy particle measurement in Earth’s radiation belt

Simulation-to-Flight 1 (STF-1) — Software condensing to support CubeSat implementations

Advanced Electrical Bus (ALBus) — Advances in solar arrays and high capacity batteries

CubeSat Handling Of Multisystem Precision Time Transfer (CHOMPTT) — Navigation plans for exo-planetary implementation

CubeSail — Deployment and control of a solar sail blade

NMTSat — Magnetic field, high altitude plasma density

Rsat — Manipulation of robotic arms

Ionospheric Scintillation Explorer (ISX) — Plasma fluctuations in the upper atmosphere

Shields-1 — Radiation shielding

DaVinci — High School to Grade School STEM education

8. The Little CubeSat That Could

CubeSat technology is still in its infancy, with mission success rates hovering near 50 percent. So, a team of scientists and engineers set out on a quest. Their goal? To build a more resilient CubeSat — one that could handle the inevitable mishaps that bedevil any spacecraft, without going kaput.

They wanted a little CubeSat that could.

They got to work in 2014 and, after three years of development, Dellingr was ready to take flight.

Read the Full Story: Dellingr: The Little CubeSat That Could

Artist’s concept of Lunar Flashlight. Credit: NASA

9. Going Farther

There are a handful of proposed NASA missions could take CubeSat technology farther:

CUVE would travel to Venus to investigate a longstanding mystery about the planet’s atmosphere using ultraviolet-sensitive instruments and a novel, carbon-nanotube light-gathering mirror.

Lunar Flashlight would use a laser to search for water ice in permanently shadowed craters on the south pole of Earth’s Moon.

Near-Earth Asteroid Scout, a SmallSat, would use a solar sail to propel it to do science on asteroids that pass close to Earth.

All three spacecraft would hitch rides to space with other missions, a key advantage of these compact science machines.

Expedition 56 Flight Engineer Serena Auñón-Chancellor installs the NanoRacks Cubesat Deployer-14 (NRCSD-14) on the Multipurpose Experiment Platform inside the Japanese Kibo laboratory module. The NRCSD-14 was then placed in the Kibo airlock and moved outside of the space station to deploy a variety of CubeSats into Earth orbit. Credit: NASA

10. And We’re Just Getting Started

Even if they’re never revived, the team considers MarCO a spectacular success.

A number of the critical spare parts for each MarCO will be used in other CubeSat missions. That includes their experimental radios, antennas and propulsion systems. Several of these systems were provided by commercial vendors, making it easier for other CubeSats to use them as well.

More small spacecraft are on the way. NASA is set to launch a variety of new CubeSats in coming years.

“There’s big potential in these small packages,” said John Baker, the MarCO program manager at JPL. “CubeSats — part of a larger group of spacecraft called SmallSats — are a new platform for space exploration affordable to more than just government agencies.”

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How NASA Earth Data Aids America

Today we roll out a new communications project that highlights some of the many ways that NASA’s Earth observations help people strengthen communities across the United States.

Space for U.S. features stories on how Earth science data is used to make informed decisions about public health, disaster response and recovery and environmental protection. By highlighting advanced technology from a global perspective, our data helps provide people achieve groundbreaking insights.

For example, a family-owned coffee company in Maine used our sunlight, wind and temperature data to determine the placement of their power-generating solar wall.

Space for U.S. features 56 stories illustrating how our science has made an impact in every state in the nation as well as the District of Columbia, Puerto Rico and regions along the Atlantic, Pacific, Gulf of Mexico, and the Great Lakes.

For six decades, we’ve used the vantage point of space to better understand our home planet and improve lives. Using Space for U.S., you can browse through stories about how applied Earth science either by state or by topics such as animals, disasters, energy, health, land and water. Each click brings you a story about how people are putting NASA data to work.

Explore the true stories behind the innovative technology, groundbreaking insights, and extraordinary collaboration happening right here in the United States with Space for U.S.

Check out “Space for U.S.” today! www.nasa.gov/spaceforus

For more information on NASA Earth, head to www.nasa.gov/Earth or https://appliedsciences.nasa.gov.

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What Makes Something A Planet, According To An Astrophysicist?

“A dolphin may look like a fish, but it’s really a mammal. Similarly, the composition of an object is not the only factor in classifying it: its evolutionary history is inextricably related to its properties. Scientists will likely continue to argue over how to best classify all of these worlds, but it’s not just astronomers and planetary scientists who have a stake in this. In the quest to make organizational sense of the Universe, we have to confront it with the full suite of our knowledge.

Although many will disagree, moons, asteroids, Kuiper belt and Oort cloud objects are fascinating objects just as worthy of study as modern-day planets are. They may even be better candidates for life than many of the true planets are. But each object’s properties are inextricably related to the entirety of its formation history. When we try to classify the full suite of what we’re finding, we must not be misled by appearances alone.”

You’ve heard about the IAU’s definition, where in order to be a planet, you must pull yourself into hydrostatic equilibrium, orbit the Sun and nothing else, and gravitationally clear your orbit. You’ve also heard about the controversial new definition from geophysical/planetary science arguments, that planets should be based on their ability to pull themselves into a spheroidal shape alone.

Well, what about a third way: defining planets (and a whole classification scheme) based on astrophysical concerns alone? It’s time to start thinking about it!

Observations of Earth, Soyuz, moon and Space Shuttle Endeavor made from the International Space Station.

source: images.nasa.gov

Why 2020 Might Be The Best Geminid Meteor Shower Of All-Time

“As the large parent body of the Geminids, asteroid 3200 Phaethon, continues on its tight orbit around the Sun, it will continue to expel matter and be torn apart, bit by tiny bit. The asteroid is about the size of the one that struck Earth 65 million years ago, causing our last great mass extinction. But instead of colliding with us all at once, this ~6 km wide asteroid is slowly dissipating in the presence of the Sun, creating tails of matter and ions but also an ever-thickening debris stream.

With each mid-December that rolls past, Earth slams through that debris stream, creating a show that gets progressively more spectacular with each set of orbits that regularly tick by. Over the past 15 years, the Geminids have regularly been one of the two best displays of meteor showers on Earth, and it’s eminently possible that 2020 will set a new record. The Moon, the Earth, and all of the other predictable conditions are just right for a spectacular show. If the clouds cooperate on December 13 and 14, treat yourself to the greatest natural show of the year. With all that 2020 has brought us, we can all use a cosmic treat like this one.”

Can everyone just have a good thing to enjoy? Can we all just have something nice that we don’t have to fight over? Well, nature might deliver what humanity has been unable to bring us for 2020: a natural show that can’t be stopped by anything, except for clouds. 

Get your Geminid fix today, and then look up on December 13/14 to fully enjoy the show!

Millisecond Pulsar with Magnetic Field Structure

A pulsar is a rapidly rotating neutron star that emits pulses of radiation (such as X-rays and radio waves) at regular intervals. A millisecond pulsar is one with a rotational period between 1 and 10 milliseconds, or from 60,000 to 6,000 revolutions per minute. Pulsars form in supernova explosions, but even newborn pulsars don’t spin at millisecond speeds, and they gradually slow down with age. If, however, a pulsar is a member of a binary system with a normal star, gas transferred from the companion can spin up an old, slow pulsar to the millisecond range.

Credit: NASA, Dana Berry: Lead Animator Michael McClare (HTSI)

Shredded Star Leads to Important Black Hole Discovery

This artist’s illustration shows the region around a supermassive black hole after a star wandered too close and was ripped apart by extreme gravitational forces. Some of the remains of the star are pulled into an X-ray-bright disk where they circle the black hole before passing over the “event horizon,” the boundary beyond which nothing, including light, can escape. The elongated spot depicts a bright region in the disk, which causes a regular variation in the X-ray brightness of the source, allowing the spin rate of the black hole to be estimated. The curved region in the upper left shows where light from the other side of the disk has been curved over the top of the black hole.

This event was first detected by a network of optical telescopes called the All-Sky Automated Survey for Supernovae (ASASSN) in November 2014. Astronomers dubbed the new source ASASSN14-li and traced the bright flash of light to a galaxy about 290 million light years from Earth. They also identified it as a “tidal disruption” event, where one cosmic object is shredded by another through gravity.

Astronomers then used other telescopes including a flotilla of high-energy telescopes in space — NASA’s Chandra X-ray Observatory, ESA’s XMM-Newton and NASA’s Neil Gehrels Swift observatory — to study the X-rays emitted as the remains of a star swirled toward the black hole at the center of the galaxy.

The tidal disruption in ASASSN-14li is intriguing because it allowed astronomers to measure the spin rate of the black hole. A black hole has two fundamental properties: mass and spin. While it has been relatively easy for astronomers to determine the mass of black holes, it has been much more difficult to get accurate measurements of their spins.

This debris from the shredded star gave astronomers an avenue to get a direct measure of the black hole’s spin in ASASSN-14li. They found that the event horizon around this black hole is about 300 times the diameter of the Earth, yet rotates once every two minutes (compared to the 24 hours it takes to complete one rotation). This means that the black hole is spinning at least half as fast as the speed of light.

Scientists have determined spin rates for some stellar-mass black holes (those that typically weigh between 5 and 30 solar masses) in our Milky Way galaxy by observing rapid and regular variations in their X-ray brightness. A few supermassive black holes have shown similar variations, but they were only observed to repeat over a few cycles, rather than the 300,000 cycles seen for ASASSN-14li. With only a few cycles, the association of the variations with the spin of the black hole is not secure.

These results will likely encourage astronomers to observe future tidal disruption events for long durations to look for similar, regular variations in their X-ray brightness. source