Swift’s telescope reveals birth, deaths and collisions of stars through 1 million snapshots in UV
August 21, 2018
Research Professor of Astronomy and Astrophysics, Pennsylvania State University
Michael Siegel is a Research Professor at Pennsylvania State University and receives research funding from NASA.
Pennsylvania State University provides funding as a founding partner of The Conversation US.
Imagine if the color camera had never been invented and all our images were in black and white. The world would still look beautiful, but incomplete. For thousands of years, that was how humans saw the universe. On Earth, we can only see part of the light that stars emit.
Much of what we can’t see – in the infrared, the ultraviolet, the X-ray and the gamma ray wavelengths – is blocked by the Earth’s atmosphere. For the most part, this is a good thing. The atmosphere traps infrared light keeping the Earth warm at night and blocks high-energy ultraviolet light, X-rays and gamma rays, keeping us safe from deadly cosmic radiation, while letting in visible portions of the spectrum of light. For astronomers, however, this has a drawback: We look at the universe with one eye shut, unable to receive all of the information the universe is sending to us.
Visible light is just a tiny part of the electromagnetic spectrum.
Launched on November 20, 2004, and orbiting an altitude of 340 miles, NASA’s Neil Gehrels Swift Observatory has three telescopes that monitor the universe using wavelengths of light that are blocked by Earth’s atmosphere. These included the X-Ray Telescope, the gamma-ray-sensitive Burst-Alert Telescope and the Ultraviolet Optical Telescope (UVOT). The UVOT recently delivered its 1 millionth image – data that astrophysicists like me use to gain insights into everything from the origins of the universe to the chemical composition of nearby comets.
Watching the birth of black holes
Swift’s primary mission is to study the afterglow of gamma ray bursts (GRBs) – which document the birth of black holes. Black holes are forged in the most violent explosions in the universe – the explosion of a massive star or the merging of two neutron stars (the shriveled husks left over from past stellar explosions). These explosions are so powerful – producing tens to hundreds of billions of times more energy than the sun – that even though they occur billions of light years away from Earth, they can still be detected by instruments like Swift. In fact, the first GRBs were detected by the Vela satellites, which were built to detect the explosions of nuclear weapons.
Over nearly 14 years, Swift has studied over a thousand GRBs. In doing so, it has revealed what powers them and given us glimpses into the furthest reaches of the cosmos, to the time when the first stars were being formed after the Big Bang.
However, one of the things you learn working on a space telescope mission is that if you build it, they will come. The mission provides capabilities to the community of astrophysicists – simultaneous X-ray/UV imaging and a rapid response to requests to observe and photograph specific sections of the sky – which are only available to Swift. We can focus our telescopes on an object of interest within hours of a “Target of Opportunity” request through our website, something no other mission can do. UVOT also fills an important niche by observing larger areas of the sky than can be observed with the more powerful UV instruments aboard the Hubble Space Telescope. These capabilities have proved a boon to the community and enabled study all sorts of objects and phenomenon beyond GRBs.
Swift’s ultraviolet-aided discoveries
Nearby galaxies are full of activity with new stars being formed. Swift is able to capture panoramic ultraviolet images that highlight the youngest, most massive stars in these galaxies. This gives us insight into what the universe has been doing over the last few hundred million years. My research team’s work has focused on nearby galaxies – like Andromeda and the Magellanic Clouds – to reveal what processes drive their past and ongoing star formation.
With UVOT, we get a much better view of supernova explosions. These can occur when a white dwarf, the remnant of a star like the sun, explodes, or during the final death throes of a massive star, more than eight times the mass of the sun. These events generate enormous amounts of ultraviolet light, and Swift has a unique ability to observe them within hours of discovery.
Comets sweep through our solar system, transforming from a frozen solid ball to a vapor as they approach the sun and creating magnificent tails of ionized particles. Swift studies these comets, and analyzes their chemical composition by breaking the light they emit into different wavelengths. Swift also allows scientists to measure a comet’s rotation by seeing how the light changes over time. This has revealed that violent eruptions on the comet surface can dramatically alter a comet’s path.
One of the most exciting discoveries that Swift made was connected with the recent discovery of gravitational waves by the Laser Interferometer Gravitational-Wave Observatory (LIGO). Gravitational waves are distortions in the fabric of spacetime created by the motions of extremely massive objects. In August of 2017, two neutrons stars collided in a distant galaxy, creating gravitational waves powerful enough to be detected on Earth. Swift was one of an army of telescopes that looked for the source of the gravitational waves. The mad scramble over those few days led to one of the most exciting discoveries of the last decade – a luminous afterglow from the source of the gravitational waves. This has opened up new branches of science by connecting a new way of studying the universe – through gravitational waves – to the traditional way – through light.
UVOT has been taking snapshots of the universe since 2004 and finally piled up its millionth image. Its success is a testament to the international team of engineers, scientists and staff at the three institutions that support it – the Pennsylvania State University; Mullard Space Science Laboratory in Surrey, England; and NASA’s Goddard Space Flight Center in Greenbelt, Maryland. It has been my privilege to be a part of this team for the last nine years. What does the future hold for UVOT? We hope to find more sources of gravitational waves, survey nearby galaxies, study even more supernovae, and monitor how objects in the universe change over time.
Here’s to the next million images.
Ancestor of all life on Earth evolved earlier than we thought, according to our new timescale
August 20, 2018
PhD candidate in Paleobiology, University of Bristol
Holly Betts receives funding from NERC GW4+ DTP.
University of Bristol provides funding as a founding partner of The Conversation UK.
Science may have enabled us to travel in space and trace the history of the entire universe, but it has not yet been able to answer exactly how and when life first arose on our planet. Traditionally, scientists have used the fossil record to try to answer these questions. Yet, as palaeontologists are all too aware, fossils are increasingly hard to find as we move backwards in time.
In fact, we don’t have a lot of rock available to study that is older than two and a half billion years. This is due to the Earth’s rock recycling system in which old rocks are destroyed through weathering processes, with the remains getting recycled into new rocks. This causes any rocks that we do have to be highly reworked from their original composition. Often they don’t contain any biological remains at all. Even the rare fossils that we do find are often very difficult to identify and cannot be easily linked to any specific group of modern organisms.
In our new study, published in Nature Ecology and Evolution, we decided to try and approach the construction of a timescale for life in a new way. This involved using the wealth of genetic data that we now have for organisms living today and applying a molecular clock, a method to decipher the past by reading the stories written in the genes of living organisms.
All life inherits genetic information from the previous generation, and this gradually changes over time as evolutionary events take place. The methodology works on the basis that the differences in the genomes of two extant (living) species, for example a human and a bacterium, have accumulated in a manner that is roughly proportional to the time since they had a common ancestor. Fossils still play a vital role in this approach by acting as a rough guide to the age of common ancestors, and the molecular clock is used to update these estimates.
Our study combines the molecular data of 29 genes from a total of 102 living organisms (we also used nine fossils for calibration). The living organisms come from right across the tree of life – including bacteria, archaea (single-celled microorganisms) and eukaryotes (multi-celled organisms such as plants and animals).
Including fossils in the process is vital to the analysis because they help to link the events in real time. Fossils tell us that a lineage must have existed prior to the age of the fossil, simply because the fossil is there. This method is most important for the reconstruction of life at its earliest points, because we have so little fossil material to work with. However, until now, this is precisely where it has been applied the least.
A timescale for the evolution of life on Earth summarising the findings of the new study. University of Bristol
Our results – a timescale for the origin and evolution of life – do come with fairly large uncertainties on the age estimates for each of the nodes, the places on the tree where species have a common ancestor. This is especially true for the most ancient parts of the tree and those parts where we have the least data, either fossil or molecular.
However, the fact that we capture uncertainty is promising, as it indicates that our timescale is not over confident by showing precise, but false, ages. Instead it means that as new extant lineages and fossils continue to be discovered, they can be added to the analysis to both refine and update it – possibly resulting in a higher degree of precision in the future.
The ancestor of all organisms
We find that the “last universal common ancestor” – a hypothetical very early single cell from which all life on Earth descended – existed prior to the “late heavy bombardment”. This was a period of intense meteor bombardment sustained by our planet about 3.9 billion years ago. This is significantly earlier than the currently accepted oldest fossil evidence would suggest (estimating 3.5-3.8 billion years ago).
The oldest confirmed fossils are from about 3.4 billion years ago, while the oldest potential fossils have been found on Greenland and date back to about 3.8 billion years ago. There’s also a suggestion that carbon found in a 4.1 billion-year-old mineral called zircon could be biological in nature. However, scientists have so far been unable to confirm that.
Some researchers think it would have been impossible for life to survive the late heavy bombardment, so that our oldest ancestor must be from after this phase. There are claims that the event would have sterilised the plants and vaporised any water around at the time. However, there are some recent mathematical models which suggest that pockets suitable for life could have remained.
We found that the crown groups of the two main lineages of life – bacteria and archaea – appeared almost one billion years after the last common universal ancestor. Eukaryotes, on the other hand, diverged relatively late in Earth’s history, about 1.8 billion years ago. This finding is consistent with previous studies.
Our timescale also allowed us to look at ancient events such as the “mitochondrial endosymbiosis” – the process which formed the mitochondria, the organelles that power our cellular respiratory systems. This important event in the history of the eukaryotes occurred close to when they first appeared, suggesting that it helped to drive their subsequent rapid spread.
We hope that our study will be a good starting point for probing the mysteries of evolution at this extremely early time in Earth’s history.
Attorney General DeWine Files Lawsuit to Recover Public Funds Related to ECOT
Ohio Attorney General Mike DeWine
August 21, 2018
COLUMBUS — Ohio Attorney General Mike DeWine today filed litigation to recover public funds disbursed by the Electronic Classroom of Tomorrow (ECOT), including claims against affiliated companies and officers of the defunct charter school. The suit follows yesterday’s amended court order granting assignment of claims to the State of Ohio.
Defendants in today’s lawsuit include:
- William Lager, of Columbus, Founder of ECOT
- Altair Learning Management I, Inc., of Columbus, which served as ECOT’s operator and management company
- IQ Innovations, LLC, of Columbus, which provided ECOT with curricular materials and related services
- Rick Teeters, of Daytona Beach, Florida; Superintendent of ECOT
- Michelle Smith, of Bristolville, Treasurer of ECOT
- Christopher Meister, of Worthington, Vice President of Accounting for ECOT
- Ann Barnes, of Grove City, Education Management Information System (EMIS) Director for ECOT
- Regina Lukich, of Upper Arlington, Director of Federal Programs for ECOT
The lawsuit alleges that:
- The ECOT officers named are strictly and personally liable for disbursements made by the charter school without authority in Ohio law
- Lager had a fiduciary duty to ECOT and violated that duty when companies in which he had substantial interest (Altair and IQ) did business with ECOT
- ECOT’s contracts with IQ Innovations were void and unlawful due to Lager’s substantial interest in the company
- Lager violated the Ohio Corrupt Practices Act
The lawsuit seeks to recover from the ECOT officers any funds improperly received by ECOT for students not properly documented in its 2015-2016 and 2016-2017 full time equivalency (FTE) review conducted by the Ohio Department of Education, as well as funds improperly paid to IQ Innovations under contracts alleged to violate Ohio law. The lawsuit also seeks to recover all profits Lager received from ECOT’s contracts with Altair and IQ. Additionally, the lawsuit seeks to collect the penal amount of a treasurer’s bond issued to Smith.
After ECOT’s closure earlier this year, the Ohio Attorney General’s Office requested that the court-appointed official overseeing ECOT’s dissolution seek a court order assigning any of ECOT’s remaining recovery claims to the Attorney General. Franklin County Common Pleas Court Judge Michael J. Holbrook assigned the claims on July 26th and issued a clarifying order yesterday, which allowed for today’s lawsuit filing. Today’s lawsuit is separate from other legal proceedings where ECOT challenged the Ohio Department of Education’s actions pursuant to the FTE review.
Attorney General DeWine issued the following statement on today’s lawsuit filing:
“My office has been in court for over two years working to hold ECOT accountable. I will continue to be aggressive in seeking to recover public funds from ECOT, its affiliates, and Mr. Lager that they improperly received.”
A copy of today’s lawsuit is available on the Ohio Attorney General’s website.