Matt Williams, Author at Universe Today

April 6, 2019April 6, 2019 by Matt Williams

Now We Know That Dark Matter Isn’t Primordial Black Holes

The early universe. Credit: Tom Abel & Ralf Kaehler (KIPACSLAC)/ AMNH/NASA

For over fifty years, scientists have theorized that roughly 85% of matter in the Universe’s is made up of a mysterious, invisible mass. Since then, multiple observation campaigns have indirectly witnessed the effects that this “Dark Matter” has on the Universe. Unfortunately, all attempts to detect it so far have failed, leading scientists to propose some very interesting theories about its nature.

One such theory was offered by the late and great Stephen Hawking, who proposed that the majority of dark matter may actually be primordial black holes (PBH) smaller than a tenth of a millimeter in diameter. But after putting this theory through its most rigorous test to date, an international team of scientists led from the Kavli Institute for the Physics and Mathematics of the Universe (IPMU) has confirmed that it is not.

April 4, 2019April 5, 2019 by Matt Williams

The Starhops Have Begun!

SpaceX's first detailed render of the Starship reentering Earth's atmosphere. Credit: SpaceX

According to Elon Musk, SpaceX’s Starship Hopper just completed its inaugural hop test at the company’s South Texas Launch Site. As the first of many, this test is intended to validate the sophisticated Raptor engines that will be used aboard the full-scale Starship spacecraft, which is intrinsic to Musks’ long-term vision of providing intercontinental flights and making commercial trips to the Moon and Mars.

April 3, 2019April 3, 2019 by Matt Williams

India Destroyed a Satellite With a Missile Last Week, and Pieces Were Thrown Into an Orbit That Risks the International Space Station

Graphic showing the cloud of space debris that currently surrounds the Earth. Credit: NASA's Goddard Space Flight Center/JSC

Last week, in a move that left many perplexed, the nation of India destroyed one of its own satellites. According to a statement made by Prime Minister Narendra Modi, this operation (“Mission Shakti”) was conducted using a new type of anti-satellite missile. With this one act, Modi claimed that India had “established itself as a space power”, effectively joining the United States, Russia and China.

Unfortunately, this demonstration has created a cloud of orbital debris in Low Earth Orbit (LEO). According to a recent statement made by NASA Administrator Jim Bridenstine, this debris poses an “unacceptable” threat to the International Space Station. In this sense, by flexing its muscle as a space power, India may have caused some serious disruption to international efforts in space.

April 3, 2019April 3, 2019 by Matt Williams

Starhopper Tests Have Gotten Delayed Because of “Ice Formation in the Cryogenic Propellant Prevalves”

SpaceX is continuing with the development of their Starship Hopper, a miniature, stainless steel version of its proposed super-heavy lift vehicle known as the Starship. Most recently, test were conducted on the revolutionary heat shield that will protect the Hopper once it reenters Earth’s atmosphere, and a new rendering was released that showed the final version entering the atmospheres of Earth and Mars.

Another recent development has to do with the first scheduled test of the miniature Starship, which began in earnest last week. Unfortunately, there has been a bit of a delay due to some technical issues with the cryogenic fuel tanks. As usual, Musk made the announcement via twitter in response to questions about when the much-anticipated flight test will happen, which has been delayed multiple times now.

April 2, 2019April 2, 2019 by Matt Williams

Satellites Watched a Huge Fireball Explode Above the Bering Sea Late Last Year

NASA's MODIS instrument, aboard the Terra satellite, captured this true-color image showing the remnants of a meteor's passage, seen as a dark shadow cast on thick, white clouds on Dec. 18, 2018. Credit: NASA GSFC

When a meteor strike the Earth’s atmosphere, a magnificent (and potentially deadly) explosion is often the result. The term for this is “fireball” (or bolide), which is used to describe exceptionally bright meteor explosions that are bright enough to be seen over a very wide area. A well-known example of this is the Chelyabinsk meteor, a superbolide that exploded in the skies over a small Russian town in February of 2013.

On December 18th, 2018, another fireball appeared in the skies over Russia that exploded at an altitude of about 26 km (16 mi) above the Bering Sea. The resulting debris was observed by instruments aboard the NASA Terra Earth Observation System (EOS) satellite, which captured images of the remnants of the large meteor a few minutes after it exploded.

March 28, 2019March 28, 2019 by Matt Williams

SpaceX Releases a New Render of What the All-Steel Starship Will Look Like Returning to Earth

The design for SpaceX’s Starship (aka. Big Falcon Rocket) is really starting to come together! Over the holidays, sections of the Starship Hopper (a miniature version of the Starship) were photographed being put together at the company’s South Texas Launch Site. By mid-January, the parts were fully-integrated, forming the body of the stainless-steel prototype that would test the spacecraft’s overall architecture.

What followed, earlier this month, were tests of the Starship’s hexagonal heat shields to determine if they would offer sufficient protection during re-entry. And now, in anticipation of the spacecraft’s eventual launch, SpaceX released an eye-popping new rendering of the Starship that shows what it would look like reentering Earth’s atmosphere.

March 27, 2019November 21, 2021 by Matt Williams

Maybe Self-Replicating Robot Probes are Destroying Each Other. That’s Why We Don’t See Them

SETI's Allen Telescope Array monitor the stars for signs of intelligent life (SETI.org)

During the 1940s, Hungarian-American scientist John von Neumann developed a mathematical theory for how machines could endlessly reproduce themselves. This work gave rise to the idea of “von Neumann probes“, a class of self-replicating interstellar probes (SRPs) that could be used to do everything from exploring the Universe to seeding it with life and intervening in species evolution.

Some have naturally suggested that this be a focus of SETI research, which would entail looking for signs of self-replicating spacecraft in our galaxy. But as is always the case with proposals like these, the Fermi Paradox eventually reasserts itself by asking the age-old question – “Where is everybody?” If there are alien civilizations out there, why haven’t we found any evidence of their SRPs?

March 25, 2019March 25, 2019 by Matt Williams

Asteroid Bennu has Already Thrown Material off into Space 11 Times Since OSIRIS-REx Arrived

This asteroid Bennu ejecting particles from its surface on January 19 was created by combining two images taken by the NavCam 1 imager onboard NASA’s OSIRIS-REx spacecraft. Credit: NASA/Goddard/University of Arizona/Lockheed Martin

On Dec. 31st, NASA’s Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer (OSIRIS-REx) rendezvoused with the asteroid 101955 Bennu. As part of an asteroid sample-return mission, NASA hopes that material from this near-Earth Asteroid (NEA) will reveal things about the history of the Solar System, the formation of its planets, and the origins of life on Earth.

Since the spacecraft established orbit around the asteroid, it has witnessed some interesting phenomena. This includes the first-ever close-up observations of particle plumes erupting from an asteroid’s surface. Since that time, the mission team has kept an eye out for these eruptions, which has allowed them to witness a total of 11 “ejection events” since the spacecraft first arrived.

March 22, 2019March 22, 2019 by Matt Williams

Pulsar Seen Speeding Away From the Supernova That Created it

Observations using the Very Large Array (orange) reveal the needle-like trail of pulsar J0002+6216 outside the shell of its supernova remnant, shown in image from the Canadian Galactic Plane Survey. The pulsar escaped the remnant some 5,000 years after the supernova explosion. Credit: NRAO

When a star exhausts its nuclear fuel towards the end of its lifespan, it undergoes gravitational collapse and sheds its outer layers. This results in a magnificent explosion known as a supernova, which can lead to the creation of a black hole, a pulsar or a white dwarf. And despite decades of observation and research, there is still much scientists don’t know about this phenomena.

Luckily, ongoing observations and improved instruments are leading to all kinds of discoveries that offer chances for new insights. For instance, a team of astronomers with the National Radio Astronomy Observatory (NRAO) and NASA recently observed a “cannonball” pulsar speeding away from the supernova that is believed to have created it. This find is already providing insights into how pulsars can pick up speed from a supernova.

March 20, 2019March 20, 2019 by Matt Williams

LIGO Just Got a Big Upgrade, Will Begin Searching for Gravitational Waves Again on April 1st

The Laser Interferometer Gravitational-Wave Observatory is made up of two detectors, this one in Livingston, La., and one near Hanford, Wash. The detectors use giant arms in the shape of an "L" to measure tiny ripples in the fabric of the universe. Credit: Caltech/MIT/LIGO Lab

In February of 2016, scientists at the Laser Interferometer Gravitational-wave Observatory (LIGO) made history by announcing the first-ever detection of gravitational waves (GWs). These ripples in the very fabric of the Universe, which are caused by black hole mergers or white dwarfs colliding, were first predicted by Einstein’s Theory of General Relativity roughly a century ago.

About a year ago, LIGO’s two facilities were taken offline so its detectors could undergo a series of hardware upgrades. With these upgrades now complete, LIGO recently announced that the observatory will be going back online on April 1st. At that point, its scientists are expecting that its increased sensitivity will allow for “almost daily” detections to take place.