Division of GPS graduate program FAQ
For this year only (2025-26 application cycle), we will accept GRE scores as late as January 15th. See the main admissions page for more information.
The GPS Division uses this rubric to assess applications to our graduate program. While we do not formally score the applications or have any cut-off criteria for admissions, this document summarizes the qualities and skills that we seek in future graduate students in our program.
General questions about the Geological and Planetary Sciences division
We seek candidates who are passionate about STEM and research. We expect your application to show that you mastered advanced courses in your relevant field. It is often helpful if applicants have had previous research, field, or laboratory experience, but it is not required. Teaching, mentoring, or science communications experience is also helpful as it exhibits familiarity with your subject matter, but it is not required. Examples of critical and independent thinking are key; your career as a graduate student will focus more on original research than coursework. Finally, we are interested in your life experiences, in particular how your personal background has equipped you to work within diverse communities as well as situations where you faced and overcame a challenge.
The GPS Division accepts applications to six different options: environmental science and engineering, geobiology, geochemistry, geology, geophysics, and planetary science. Applications will also be shared across options where there is overlap. Therefore students enter our program with a range of backgrounds. In addition to the geosciences, they come from: applied mathematics, physics, chemistry, biology, engineering, etc. We expect typical STEM introductory coursework for an undergraduate STEM degree (e.g., calculus, first-year physics, first-year chemistry, etc.) and specialized higher level courses in one or more STEM disciplines.
At Caltech we have a unique organizational structure. An "option" is similar to a "department" at other institutions. Each option lives within a "division," and many of the GPS faculty are associated with more than one option. In the GPS Division, our options are geology, geochemistry, geobiology, geophysics, and planetary science. The GPS graduate program also interacts closely with the Environmental Science and Engineering (ESE) program at Caltech and there is overlap between students in ESE and GPS in advisors and coursework.
When you apply to Caltech you apply to an option, not a division. Your option will determine which classes are required for the completion of your degree. These requirements are similar across the GPS division, but not identical. At Caltech, our small size allows us to be flexible in terms of course requirements and research projects often span multiple options. It is also common to work closely with advisers that are outside of your option. We strongly encourage applicants to contact potential advisers to seek advice on the option to which you apply.
There are typically between 120 and 140 graduate students in the GPS Division, and a typical incoming class is roughly 20-25 students (including the ESE program). Numbers of students admitted annually by option vary, but are typically between 4-12 per year.
The number of applications varies between options, but we typically receive over 250 applications in the GPS Division each year. Each option is dedicated to giving every application a full review.
Students that complete their course work are eligible to receive a Masters degree, typically after two years. The average time to complete the PhD is 5.5 years. Many students finish in 5 years, and almost all students finish within 6 years. The GPS Division only admits students with an intention to complete a Ph.D.; we do not accept applications to a masters program.
Pathways differ but many continue within academia, first as postdoctoral researchers and then as faculty at Universities or research scientists at centers run by NASA, DOE, NOAA or USGS. Some of our former students have moved to teaching-focused institutions or positions outside of academia, including industry, consulting, policy, and science journalism.
Yes. Graduate students in the GPS division are expected to TA one term per year. Caltech is on the quarter system and has three "teaching" terms: fall, winter, and spring. We do not require our first-year students to serve as TA's. Most of the classes for which GPS students serve as TAs are graduate level classes, and these are an excellent opportunity to hone your experience as an instructor.
Graduate students are paid a stipend of $46,500 a year (starting October 1, 2024). This typically increases annually to account for cost-of-living increases in Pasadena. Stipends are uniform across GPS and do not depend on whether the student is serving as a teaching assistant. Caltech also offers a subsidized health insurance plan that covers a majority of physical and mental health needs as well as a Health Center on campus. There is also subsidized dental and vision insurance available.
You will receive your stipend payment at the end of every month, beginning with your first month at Caltech. Most students start in October, but each year some students start in the summer based on research opportunities. Caltech offers subsidized housing (see next question) and subsidized health care (see previous question). If the initial costs are a barrier, you can apply for a New Graduate Student Start-Up (NGSS) Loan of $2,500 from Caltech, which is disbursed during orientation week and payments begin 6 months later. For further details, you can confidentially contact the Dean's Office or the Graduate Options Manager for GPS, Julie Lee ([email protected]).
Yes, unfortunately. However, the stipend adequately covers housing costs for students. Many students choose to live with roommates to reduce costs, as housing near campus can be expensive. Information about graduate housing in the Catalina apartments and other Caltech-owned and rent-controlled properties is available through Caltech Housing (https://housing.caltech.edu/).
GPS students are guaranteed funding through a Division fellowship for the first five terms at Caltech (through the fall term of the second year). Following this, students are typically supported by one or more research advisers. The Division is committed to funding students throughout their graduate career. We strongly encourage and support students to apply for external fellowships, because of the experience in writing proposals, prestige of having received the fellowship, and autonomy in funding. These including but not limited to:
● NSF Graduate Research Fellowship
● DOE Office of Science Graduate Fellowship
● National Defense Science & Engineering Graduate Fellowship
● Soros Fellowship for New Americans
● Future Investigators in NASA Earth and Space Science and Technology (FINESST)
Assistance and advice for applying to fellowships is offered by the Caltech Fellowships Advising office. You should also discuss with your advisor or prospective advisor.
Yes. The GPS Division holds an Open House weekend for admitted prospective students in late February or early March of each year. We can generally provide support for the cost of flights and accommodation during the visit (we often cost-share with other universities that hold similar events). We highly recommend that prospective students come to campus and interact with potential faculty advisors and their research groups, meet potential members of your cohort (and your future collaborators!), and explore campus and Pasadena. If you are unable to attend the Open House weekend, you can contact the GPS Graduate Options Manager, Julie Lee, [email protected], to schedule an individual visit.
General questions about the application
Applications are typically due on December 15th each year, although we encourage students to visit the graduate admissions website for up-to-date information.
The components of the application that we evaluate are: applicant transcript, applicant statement of purpose (2 pages), resume/CV (2 pages; particularly as relating to demonstrated research experience and outputs, STEM teaching/outreach, leadership activities, work experience and time management), GRE scores, and 3 letters of recommendation.
Each option handles interviews differently. In some cases, a faculty member may contact you to discuss your interests. Some options do zoom interviews with shortlisted applicants.
For students from non-English speaking countries, standard tests like the TOEFFL or PTE tests are required. English competency is evaluated by the test scores, application, and in some cases during an interview. For more information see the ‘Questions specific to international students' section.
Decisions are typically made by the end of January. We will provide information on our offer of admission via email.
There is a cost of $100 to apply to graduate school at Caltech. Fee waivers are available as discussed next.
A fee waiver is available and we encourage anyone for whom the fee represents a burden to apply. The fee waiver is available within the online admissions system and is submitted to the Graduate Studies Office.
Absolutely not. Admissions committees and potential faculty advisers do not have access to information regarding fee waivers. If the fee, which supports the Graduate Admissions Office in processing the applications, represents a burden, please request the waiver without concern.
There is no GPA requirement for admission but the GPA is a factor in our admissions process as is the difficulty and breadth of courses attempted. We are aware that average GPAs vary by institution and by major.
For this year only (2025-26 application cycle), we will accept GRE scores as late as January 15th. See the main admissions page for more information.
We require GRE scores as part of our application package for geology, geochemistry, geobiology, geophysics, and planetary science. For environmental science and engineering it's recommended but not required. However, we also believe in letting every applicant showcase their academic and research success in whatever form that may take: research projects, competitions, exams, awards, experiences, etc. We consider any submitted test scores as one aspect of academic achievement, but we take a holistic approach to our application evaluation.
Our graduate students have taken many paths before arriving at Caltech. Regardless of your background, we seek to admit students who have some of the following accomplishments: have demonstrated, through their personal statement, that they are passionate in their decision to pursue a Ph.D.; have the academic background needed to be successful at Caltech (strong transcript in a rigorous curriculum that includes significant quantitative science and/or engineering coursework); previous research/scholarly experience; and, strong letters of recommendation from those who know you well and can speak to your ability to be successful at Caltech; a commitment to fostering a diverse and inclusive research community within the Division and throughout campus.
There is no list of professors who are accepting students. The GPS faculty welcome inquiries about the likelihood that there will be positions available in individual labs. This is also often a useful way to learn about new research activities in the Division. However, admissions decisions are made by each option faculty collectively and not by individuals, so please refrain from asking about likelihoods of success. A list of the current GPS faculty members can be found here.
Absolutely! However, admissions to the graduate program in each option are completed by faculty committees — you will be admitted to an option, but not directly into a faculty member's laboratory. During your first year in the graduate program you will need to complete two research projects that we call propositions. This provides an opportunity to work with two different faculty members and explore potential thesis directions. As you develop your application, we encourage you to think broadly about the opportunities in each option and across the Division. It is helpful to note in your application statement those faculty members that you feel could be suitable advisers for your research interests. Some faculty members have appointments in more than one option, and in some cases, in more than one Division. We encourage you to contact faculty individually if you are unsure about the appropriate option or Division to which you should apply.
The Statement of Purpose should reflect your motivation for applying to the PhD program. Things you can include in your statement include:
● Your motivations, your research interests and why you feel that one or more of the GPS options would be a suitable fit; this could include a list of faculty members with whom you would like to work;
● Any previous personal, educational, research, or professional experiences that qualify you for the mix of directed and independent work and creative problem-solving that you will deploy as a Ph.D.-candidate researcher;
● Concrete examples of how you solved a research problem or your insights and unique contributions to a collaborative STEM project;
● Thoughts about your future career paths and why Caltech specifically is a great choice for you;
● Extenuating circumstances and how you have overcome challenges that have impacted your career path thus far.
An ideal statement is brief (2 pages) and clearly written.
Deferrals can be granted on a case-by-case basis after the student has been officially admitted.
For further questions, you can reach out to the Graduate Options Manager for GPS, Julie Lee ([email protected]).
Questions specific to international students
If your recommenders are unable to write their letters in English or your transcript is not in English, please contact the Graduate Options Manager for GPS, Julie Lee ([email protected]).
GPA is a Grade Point Average. We are experienced with scales from different countries, so there is nothing specific you need to do.
For non-native speakers, there is a language test requirement but you will have a choice between TOEFL, IELTS, or Pearsons. In addition, Caltech offers English as a second language (ESL) courses for those who might benefit from improving their English skills. If there are reasons for why you can't take a language test, please contact the Graduate Options Manager for GPS, Julie Lee ([email protected]) and we will try to find an alternative solution if required.
We are committed to supporting international students admitted to our graduate program in the same way as our domestic students. However, we do encourage students to apply for independent funding and fellowships opportunities, as appropriate. Fellowship opportunities will vary by country, but many governments have schemes that for which STEM students can apply for to pursue a PhD. Many of these fellowships can be used for study in a foreign country. Most US government fellowships are only available for US citizens or permanent residents, but there are some that are available for international students as well:
Ultimately the admissions committee is trying to assess your potential to excel as a researcher. Ask your recommenders to write about not just about you as a student in a classroom or your grades on exams or papers, but also about your skills as a researcher, your prior research experience, or how your skills in the classroom or in teaching -- for example, critical thinking, in-class questions or discussion, insights on independent assignments, science communication skills -- can translate into skills in a research environment.
In most cases, before starting your PhD you will need to pay for a visa, SEVIS fee, and travel to Pasadena. If you use Caltech housing and health insurance, those costs can be paid later in the academic term, after you start receiving your stipend. If you need help with start-up expenses, you can apply for a New Graduate Student Start-Up (NGSS) Loan of USD $2500 that is disbursed in person during orientation.